PYRROLO[1,2-f][1,2,4]TRIAZINES USEFUL FOR TREATING RESPIRATORY SYNCITIAL VIRUS INFECTIONS

ABSTRACT

Provided herein are formulations, methods and substituted tetrahydrofuranyl-pyrrolo[1,2-f][1,2,4]triazine-4-amine compounds of Formula (I) for treating Pneumovirinae virus infections, including respiratory syncytial virus infections, as well as methods and intermediates for synthesis of tetrahydrofuranyl-pyrrolo[1,2-f][1,2,4]triazine-4-amine compounds.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of and priority to U.S. ProvisionalApplication Ser. No. 61/902,544, filed Nov. 11, 2013, the disclosure ofwhich is hereby incorporated by reference in its entirety.

FIELD

Provided herein are substitutedtetrahydrofuranyl-pyrrolo[1,2-f][1,2,4]triazine-4-amine compounds,methods and pharmaceutical formulations for treating Pneumovirinae virusinfections, particularly including respiratory syncytial virusinfections, as well as methods and intermediates useful for preparingthe compounds.

BACKGROUND

Pneumovirinae viruses are negative-sense, single-stranded, RNA virusesthat are responsible for many prevalent human and animal diseases. ThePneumovirinae sub-family of viruses is a part of the familyParamyxoviridae and includes human respiratory syncytial virus (HRSV).Almost all children will have had an HRSV infection by their secondbirthday. HRSV is the major cause of lower respiratory tract infectionsin infancy and childhood with 0.5% to 2% of those infected requiringhospitalization. The elderly and adults with chronic heart, lung diseaseor those that are immunosuppressed also have a high risk for developingsevere HRSV disease (http://www.cdc.gov/rsv/index.html). No vaccine toprevent HRSV infection is currently available. The monoclonal antibodypalivizumab is available for immunoprophylaxis, but its use isrestricted to infants at high risk, e.g., premature infants or thosewith either congenital heart or lung disease, and the cost for generaluse is often prohibitive. In addition, nucleoside analog ribavirin hasbeen approved as the only antiviral agent to treat HRSV infections buthas limited efficacy. Therefore, there is a need for anti-Pneumovirinaetherapeutics.

Examples of pyrrolo[2,3-d]pyrimidine compounds useful for treating viralinfections are described in U.S. 2012/0009147 A1 (Cho et al.), U.S.2012/0020921 A1 (Cho et al.), WO 2008/089105 A2 (Babu et al.), WO2008/141079 A1 (Babu et al.), WO 2009/132135 A1 (Butler et al.), WO2010/002877 A2 (Francom), WO 2011/035231 A1 (Cho et al.), WO 2011/035250A1 (Butler et al.), WO 2011/150288 A1 (Cho et al.), WO 2012/012465 (Choet al.), WO 2012/012776 A1 (Mackman et al.), WO 2012/037038 (Clarke etal.), WO 2012/087596 A1 (Delaney et al.), and WO 2012/142075 A1(Girijavallabhan et al.).

There remains a need for new antiviral agents useful in treatingParamyxoviridae viral infections, including Pneumovirinae viralinfections, such as HRSV infections, that are effective and haveacceptable toxicity profiles.

SUMMARY

Provided are compounds, methods, and pharmaceutical formulations for thetreatment of infections caused by the Pneumovirinae virus family,including treatment of infections caused by human respiratory syncytialvirus.

Provided is a compound of the Formula (I), or a pharmaceuticallyacceptable salt thereof:

wherein:

R¹ is H or F;

R² is H or F;

R³ is OH or F;

R⁴ is CN, C₁-C₄ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, C₃-C₄ cycloalkyl,azido, halogen, or C₁-C₂ haloalkyl;

R⁶ is OH;

R⁵ is selected from the group of H and:

wherein:

n′ is selected from 1, 2, 3, and 4;

R⁸ is selected from C₁-C₈ alkyl, —O—C₁-C₈ alkyl, benzyl, —O-benzyl,—CH₂—C₃-C₆ cycloalkyl, —O—CH₂—C₃-C₆ cycloalkyl, and CF₃;

R⁹ is selected from phenyl, 1-naphthyl, 2-naphthyl,

R¹⁰ is selected from H and CH₃;

R¹¹ is selected from H or C₁-C₆ alkyl;

R¹² is selected from H, C₁-C₈ alkyl, benzyl, C₃-C₆ cycloalkyl, and—CH₂—C₃-C₆ cycloalkyl.

DETAILED DESCRIPTION

An embodiment herein comprises a compound of Formula (I), or apharmaceutically acceptable salt thereof, wherein R¹ is H, and all othervariables, including R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², andn′ are as defined above for Formula (I).

Another embodiment herein comprises a compound of Formula (I), or apharmaceutically acceptable salt thereof, wherein R² is H, and all othervariables, including R¹, R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², andn′ are as defined above for Formula (I).

A further embodiment herein comprises a compound of Formula (I), or apharmaceutically acceptable salt thereof, wherein both R¹ and R² are H,and all other variables, including R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹,R¹², and n′ are as defined above for Formula (I).

Still another embodiment herein comprises a compound of Formula (I), ora pharmaceutically acceptable salt thereof, wherein both R¹, R², and R⁵are H, and all other variables, including R³, R⁴, R⁶, R⁷, R⁸, R⁹, R¹⁰,R¹¹, R¹² and n′ are as defined above for Formula (I).

Another separate embodiment herein comprises a compound of Formula (I),or a pharmaceutically acceptable salt thereof, wherein both R¹ and R²are H, R³ is OH, and all other variables, including R⁴, R⁵, R⁶, R⁷, R⁸,R⁹, R¹⁰, R¹¹, R¹² and n′ are as defined above for Formula (I).

Another separate embodiment herein comprises a compound of Formula (I),or a pharmaceutically acceptable salt thereof, wherein both R¹ and R²are H, R³ is F, and all other variables, including R⁴, R⁵, R⁶, R⁷, R⁸,R⁹, R¹⁰, R¹¹, R¹² and n′ are as defined above for Formula (I).

Another embodiment provided herein comprises a compound of Formula (II),or a pharmaceutically acceptable salt thereof:

wherein:

R³ is OH or F;

R⁴ is CN, C₁-C₄ alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, C₃-C₄ cycloalkyl,azido, halogen, or C₁-C₂ haloalkyl;

R⁵ is selected from the group of H and:

wherein:

n′ is selected from 1, 2, 3, and 4;

R⁸ is selected from C₁-C₈ alkyl, —O—C₁-C₈ alkyl, benzyl, —O-benzyl,—CH₂—C₃-C₆ cycloalkyl, —O—CH₂—C₃-C₆ cycloalkyl, and CF₃;

R⁹ is phenyl;

R¹⁰ is selected from H and CH₃;

R¹¹ is selected from H or C₁-C₆ alkyl;

R¹² is selected from H, C₁-C₈ alkyl, benzyl, C₃-C₆ cycloalkyl, and—CH₂—C₃-C₆ cycloalkyl.

A further embodiment comprises a compound of Formula (II), or apharmaceutically acceptable salt thereof, wherein:

R³ is OH or F;

R⁴ is CN, methyl, ethyl, ethenyl, ethynyl, azido, F, Cl, —CH₂Cl, —CH₂F,—CHF₂, or —CF₃;

and R⁵ and all other groups are as defined for Formula (II).

Also provided is an embodiment comprising a compound of Formula (II) ora pharmaceutically acceptable salt thereof, as described above, whereinR³ is F.

Also provided is an embodiment comprising a compound of Formula (II) ora pharmaceutically acceptable salt thereof, as described above, whereinR³ is OH.

Also provided is an embodiment comprising a compound of Formula (II) ora pharmaceutically acceptable salt thereof, as described above, whereinR³ is F and R⁴ is CN.

Also provided is an embodiment comprising a compound of Formula (II) ora pharmaceutically acceptable salt thereof, as described above, whereinR³ is OH and R⁴ is CN.

Also provided is an embodiment comprising a compound of Formula (II) ora pharmaceutically acceptable salt thereof, as described above, whereinboth R¹ and R² are H, R³ is F, and R⁴ is methyl, ethyl, vinyl, orethynyl.

Also provided is an embodiment comprising a compound of Formula (II) ora pharmaceutically acceptable salt thereof, as described above, whereinR³ is OH, and R⁴ is methyl, ethyl, vinyl, or ethynyl.

Also provided is an embodiment comprising a compound of Formula (II) ora pharmaceutically acceptable salt thereof, as described above, whereinR³ is F and R⁴ is halomethyl.

Also provided is an embodiment comprising a compound of Formula (II) ora pharmaceutically acceptable salt thereof, as described above, whereinR³ is OH and R⁴ is halomethyl.

Also provided is an embodiment comprising a compound of Formula (II) ora pharmaceutically acceptable salt thereof, as described above, whereinR⁵ is H.

Also provided is an embodiment comprising a compound of Formula (II) ora pharmaceutically acceptable salt thereof, as described above, whereineach of R⁵ is H, R³ is OH, and R⁴ is methyl, ethyl, vinyl, or ethynyl.

Also provided is an embodiment comprising a compound of Formula (II) ora pharmaceutically acceptable salt thereof, as described above, whereinR⁵ is H, R³ is F, and R⁴ is halomethyl.

Also provided is an embodiment comprising a compound of Formula (II) ora pharmaceutically acceptable salt thereof, as described above, whereinR⁵ are H, R³ is OH, and R⁴ is halomethyl.

Within each of the embodiments described above comprising a compound ofFormula (II), or a pharmaceutically acceptable salt thereof, wherein R⁵may be other than H, there is a further embodiment wherein all othervariables are as described for the embodiment and R⁵ is selected fromthe group of:

wherein:

-   -   R⁸ is selected from C₁-C₈ alkyl, —O—C₁-C₈ alkyl, benzyl, and        —CH₂—C₃-C₆ cycloalkyl; and    -   R¹² is selected from C₁-C₈ alkyl, benzyl, C₃-C₆ cycloalkyl, and        —CH₂—C₃-C₆ cycloalkyl.

Within each of the embodiments described immediately above there is afurther embodiment comprising a compound of Formula (II), or apharmaceutically acceptable salt thereof, wherein all other variablesare as described immediately above, except that R⁸ and R⁹ are eachselected from C₁-C₈ alkyl. Within each of the embodiments described inthe last sentence there is a further embodiment comprising a compound ofFormula (II), or a pharmaceutically acceptable salt thereof, wherein allother variables are as described immediately above, except that R⁸ andR⁹ are each selected from C₁-C₆ alkyl. Within each of the embodimentsdescribed in the last sentence there is a further embodiment comprisinga compound of Formula (II), or a pharmaceutically acceptable saltthereof, wherein all other variables are as described immediately above,except that R⁸ and R⁹ are each selected from C₁-C₆ alkyl. Within each ofthe embodiments described in the last sentence there is a furtherembodiment comprising a compound of Formula (II), or a pharmaceuticallyacceptable salt thereof, wherein all other variables are as describedimmediately above, except that R⁸ and R⁹ are each selected from C₁-C₄alkyl.

Within each of the embodiments described herein comprising a compound ofFormula (I) or of Formula (II) there is a further embodiment wherein allvariables are as defined for the particular embodiment and furthercomprising the proviso that when R³ is F, R⁴ is not methyl.

DEFINITIONS

The terms halo and halogen refer to halogen atoms selected from F, Cl,Br, and I.

“Azido” refers to an azide group, i.e. the group —N₃. The term “n” asused herein refers to an integer, such as an integer selected from 1, 2,3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20,i.e. 2 to 20 or 2-20. In some instances, “n” refers to groups ofintegers such as 1 to 3, 1 to 4, 1 to 6, 1 to 8, 2 to 4, 2 to 6, 2 to 8,etc.

The term “haloalkyl” as used herein refers to an alkyl as definedherein, wherein one or more hydrogen atoms are each replaced by a halosubstituent. For example, a (C₁-C₆)haloalkyl is a (C₁-C₆)alkyl whereinone or more of the hydrogen atoms have been replaced by a halosubstituent. Such a range includes one halo substituent on the alkylgroup t to complete halogenation of the alkyl group.

The term “(C_(1-n))haloalkyl” as used herein, wherein n is an integer,either alone or in combination with another radical, is intended to meanan alkyl radical having 1 to n carbon atoms as defined above wherein oneor more hydrogen atoms are each replaced by a halo substituent. Examplesof (C_(1-n))haloalkyl, wherein n is 2 include, but are not limited to,chloromethyl, chloroethyl, dichloroethyl, bromomethyl, bromoethyl,dibromoethyl, fluoromethyl, difluoromethyl, trifluoromethyl, fluoroethyland difluoroethyl.

The term “(C_(1-n))alkyl” as used herein, wherein n is an integer,either alone or in combination with another radical, is intended to meanacyclic, straight or branched chain alkyl radicals containing from 1 ton carbon atoms. “(C₁₋₄)alkyl” includes, but is not limited to, methyl,ethyl, propyl (n-propyl), butyl (n-butyl), 1-methylethyl (iso-propyl),1-methylpropyl (sec-butyl), 2-methylpropyl (iso-butyl), and1,1-dimethylethyl (tert-butyl or t-butyl). The abbreviation Me denotes amethyl group; Et denotes an ethyl group, Pr denotes a propyl group, iPrdenotes a 1-methylethyl group, Bu denotes a butyl group and tBu denotesa 1,1-dimethylethyl group.

The term “alkyl” refers to a hydrocarbon containing normal, secondary,or tertiary atoms. For example, an alkyl group can have 1 to 4 carbonatoms (i.e., (C₁-C₄)alkyl), 1 to 3 carbon atoms (i.e., (C₁-C₃)alkyl), or1 or 2 carbon atoms (i.e., (C₁-C₂)alkyl). Examples of suitable alkylgroups include, but are not limited to, methyl (Me, —CH₃), ethyl (Et,—CH₂CH₃), 1-propyl (n-Pr, n-propyl, —CH₂CH₂CH₃), 2-propyl (i-Pr,i-propyl, —CH(CH₃)₂), 1-butyl (n-Bu, n-butyl, —CH₂CH₂CH₂CH₃),2-methyl-1-propyl (i-Bu, i-butyl, —CH₂CH(CH₃)₂), 2-butyl (s-Bu, s-butyl,—CH(CH₃)CH₂CH₃), and 2-methyl-2-propyl (t-Bu, t-butyl, —C(CH₃)₃).“Alkyl” also refers to a saturated, branched or straight chainhydrocarbon radical having two monovalent radical centers derived by theremoval of two hydrogen atoms from the same or two different carbonatoms of a parent alkane. Typical alkyl radicals include, but are notlimited to, methylene (—CH₂—), 1,1-ethyl (—CH(CH₃)—), 1,2-ethyl(—CH₂CH₂—), 1,1-propyl (—CH(CH₂CH₃)—), 1,2-propyl (—CH₂CH(CH₃)—),1,3-propyl (—CH₂CH₂CH₂—), 1,4-butyl (—CH₂CH₂CH₂CH₂—), and the like.

“Alkenyl” is a straight or branched hydrocarbon containing normal,secondary or tertiary carbon atoms with at least one site ofunsaturation, i.e. a carbon-carbon, sp² double bond. As examples, analkenyl group can have 2 to 4 carbon atoms (i.e., C₂-C₄ alkenyl), or 2to 3 carbon atoms (i.e., C₂-C₃ alkenyl). Examples of suitable alkenylgroups include, but are not limited to, ethylene or vinyl (—CH═CH₂) andallyl (—CH₂CH═CH₂.

The term “(C_(2-n))alkenyl”, as used herein, wherein n is an integer,either alone or in combination with another radical, is intended to meanan unsaturated, acyclic straight or branched chain radical containingtwo to n carbon atoms, at least two of which are bonded to each other bya double bond. Examples of such radicals include, but are not limitedto, ethenyl (vinyl), 1-propenyl, 2-propenyl, and 1-butenyl. Unlessspecified otherwise, the term “(C_(2-n))alkenyl” is understood toencompass individual stereoisomers where possible, including but notlimited to (E) and (Z) isomers, and mixtures thereof. When a(C_(2-n))alkenyl group is substituted, it is understood to besubstituted on any carbon atom thereof which would otherwise bear ahydrogen atom, unless specified otherwise, such that the substitutionwould give rise to a chemically stable compound, such as are recognizedby those skilled in the art.

“Alkynyl” is a straight or branched hydrocarbon containing normal,secondary or tertiary carbon atoms with at least one site ofunsaturation, i.e. a carbon-carbon, sp triple bond. For example, analkynyl group can have 2 to 4 carbon atoms (i.e., C₂-C₄ alkynyl) or 2 to3 carbon atoms (i.e., C₂-C₃ alkyne,). Examples of suitable alkynylgroups include, but are not limited to, acetylenic (—C≡CH), propargyl(—CH₂C≡CH), and the like.

The term “(C_(2-n))alkynyl”, as used herein, wherein n is an integer,either alone or in combination with another radical, is intended to meanan unsaturated, acyclic straight or branched chain radical containingtwo to n carbon atoms, at least two of which are bonded to each other bya triple bond. Examples of such radicals in which n is 4 include, butare not limited to, ethynyl, 1-propynyl, 2-propynyl, and 1-butynyl. Whena (C_(2-n))alkynyl group is substituted, it is understood to besubstituted on any carbon atom thereof which would otherwise bear ahydrogen atom, unless specified otherwise, such that the substitutionwould give rise to a chemically stable compound, such as are recognizedby those skilled in the art.

The term cycloalkyl refers to a cyclic aliphatic group. The cycloalkylgroups herein may be referenced by the number of carbon atoms in theirring, such as “C₃-C₄ cycloalkyl” referring to a cycloalkyl ring with 3or 4 carbon ring atoms or “C₃-C₆ cycloalkyl” indicating a cycloalkylring with 3, 4, 5, or 6 carbon ring atoms, i.e. a cyclopropyl,cyclobutyl, cyclopentyl, or cyclohexyl ring.

The term “carbocycle” or “carbocyclyl” refers to a saturated (i.e.,cycloalkyl) or partially unsaturated (e.g., cycloalkenyl,cycloalkadienyl, etc.) ring having the number of carbon atoms specified,such as 3 to 4 carbon atoms or 3 to 6 carbon atoms as a monocyclic ringsystem. In one embodiment the carbocycle is a monocycle comprising 3-6ring carbons (i.e. (C₃-C₆)carbocycle). Non-limiting examples ofmonocyclic carbocycles include cyclopropyl, cyclobutyl, cyclopentyl,1-cyclopent-1-enyl, 1-cyclopent-2-enyl, 1-cyclopent-3-enyl, cyclohexyl,1-cyclohex-1-enyl, 1-cyclohex-2-enyl, 1-cyclohex-3-enyl, andcyclohexa-1,3-dienyl rings.

Each carbocyclyl group may be substituted by 0, 1, 2, or 3 substituentsindependently selected from halogen, —OH, —CN, —NO₂, —NH₂, —NH(C₁-C₆alkyl), —N(C₁-C₆ alkyl)₂, C₁-C₆ alkyl, C₁-C₆ alkoxy, and —CF₃.

Pharmaceutical Formulations

Also provided herein is a pharmaceutical formulation comprising apharmaceutically effective amount of a compound of Formula (I) or apharmaceutically acceptable salt, solvate, and/or ester thereof, and apharmaceutically acceptable carrier or excipient. Also provided areseparate pharmaceutical formulations, each comprising a pharmaceuticallyeffective amount of a compound of Formula (II) or one of the specificcompounds of the examples herein, or a pharmaceutically acceptable salt,solvate, and/or ester thereof, and a pharmaceutically acceptable carrieror excipient.

The compounds herein are formulated with conventional carriers andexcipients, which will be selected in accord with ordinary practice.Tablets will contain excipients, glidants, fillers, binders and thelike. Aqueous formulations are prepared in sterile form, and whenintended for delivery by other than oral administration generally willbe isotonic. All formulations will optionally contain excipients such asthose set forth in the “Handbook of Pharmaceutical Excipients” (1986).Excipients include ascorbic acid and other antioxidants, chelatingagents such as EDTA, carbohydrates such as dextran,hydroxyalkylcellulose, hydroxyalkylmethylcellulose, stearic acid and thelike. The pH of the formulations ranges from about 3 to about 11, but isordinarily about 7 to 10.

While it is possible for the active ingredients to be administered aloneit may be preferable to present them as pharmaceutical formulations. Theformulations, both for veterinary and for human use, comprise at leastone active ingredient, as above defined, together with one or moreacceptable carriers and optionally other therapeutic ingredients,particularly those additional therapeutic ingredients as discussedherein. The carrier(s) must be “acceptable” in the sense of beingcompatible with the other ingredients of the formulation andphysiologically innocuous to the recipient thereof.

The formulations include those suitable for the foregoing administrationroutes. The formulations may conveniently be presented in unit dosageform and may be prepared by any of the methods well known in the art ofpharmacy. Techniques and formulations generally are found in Remington'sPharmaceutical Sciences (Mack Publishing Co., Easton, Pa.). Such methodsinclude the step of bringing into association the active ingredient withthe carrier which constitutes one or more accessory ingredients. Ingeneral the formulations are prepared by uniformly and intimatelybringing into association the active ingredient with liquid carriers orfinely divided solid carriers or both, and then, if necessary, shapingthe product.

Formulations suitable for oral administration may be presented asdiscrete units such as capsules, cachets or tablets each containing apredetermined amount of the active ingredient; as a powder or granules;as a solution or a suspension in an aqueous or non-aqueous liquid; or asan oil-in-water liquid emulsion or a water-in-oil liquid emulsion. Theactive ingredient may also be administered as a bolus, electuary orpaste.

A tablet is made by compression or molding, optionally with one or moreaccessory ingredients. Compressed tablets may be prepared by compressingin a suitable machine the active ingredient in a free-flowing form suchas a powder or granules, optionally mixed with a binder, lubricant,inert diluent, preservative, surface active or dispersing agent. Moldedtablets may be made by molding in a suitable machine a mixture of thepowdered active ingredient moistened with an inert liquid diluent. Thetablets may optionally be coated or scored and optionally are formulatedso as to provide slow or controlled release of the active ingredienttherefrom.

For infections of the eye or other external tissues e.g. mouth and skin,the formulations are preferably applied as a topical ointment or creamcontaining the active ingredient(s) in an amount of, for example, 0.075to 20% w/w (including active ingredient(s) in a range between 0.1% and20% in increments of 0.1% w/w such as 0.6% w/w, 0.7% w/w, etc.),preferably 0.2 to 15% w/w and most preferably 0.5 to 10% w/w. Whenformulated in an ointment, the active ingredients may be employed witheither a paraffinic or a water-miscible ointment base. Alternatively,the active ingredients may be formulated in a cream with an oil-in-watercream base.

If desired, the aqueous phase of the cream base may include, forexample, at least 30% w/w of a polyhydric alcohol, i.e. an alcoholhaving two or more hydroxyl groups such as propylene glycol, butane1,3-diol, mannitol, sorbitol, glycerol and polyethylene glycol(including PEG 400) and mixtures thereof. The topical formulations maydesirably include a compound which enhances absorption or penetration ofthe active ingredient through the skin or other affected areas. Examplesof such dermal penetration enhancers include dimethyl sulphoxide andrelated analogs.

The oily phase of the emulsions may be constituted from knowningredients in a known manner. While the phase may comprise merely anemulsifier (otherwise known as an emulgent), it desirably comprises amixture of at least one emulsifier with a fat or an oil or with both afat and an oil. Preferably, a hydrophilic emulsifier is includedtogether with a lipophilic emulsifier which acts as a stabilizer. It isalso preferred to include both an oil and a fat. Together, theemulsifier(s) with or without stabilizer(s) make up the so-calledemulsifying wax, and the wax together with the oil and fat make up theso-called emulsifying ointment base which forms the oily dispersed phaseof the cream formulations.

Emulgents and emulsion stabilizers suitable for use in the formulationinclude Tween® 60, Span® 80, cetostearyl alcohol, benzyl alcohol,myristyl alcohol, glyceryl mono-stearate and sodium lauryl sulfate.

The choice of suitable oils or fats for the formulation is based onachieving the desired cosmetic properties. The cream should preferablybe a non-greasy, non-staining and washable product with suitableconsistency to avoid leakage from tubes or other containers. Straight orbranched chain, mono- or dibasic alkyl esters such as di-isoadipate,isocetyl stearate, propylene glycol diester of coconut fatty acids,isopropyl myristate, decyl oleate, isopropyl palmitate, butyl stearate,2-ethylhexyl palmitate or a blend of branched chain esters known asCrodamol CAP may be used, the last three being preferred esters. Thesemay be used alone or in combination depending on the propertiesrequired. Alternatively, high melting point lipids such as white softparaffin and/or liquid paraffin or other mineral oils are used.

Pharmaceutical formulations herein comprise a combination together withone or more pharmaceutically acceptable carriers or excipients andoptionally other therapeutic agents. Pharmaceutical formulationscontaining the active ingredient may be in any form suitable for theintended method of administration. When used for oral use for example,tablets, troches, lozenges, aqueous or oil suspensions, dispersiblepowders or granules, emulsions, hard or soft capsules, solutions, syrupsor elixirs may be prepared. Compositions intended for oral use may beprepared according to any method known to the art for the manufacture ofpharmaceutical compositions and such compositions may contain one ormore agents including sweetening agents, flavoring agents, coloringagents and preserving agents, in order to provide a palatablepreparation. Tablets containing the active ingredient in admixture withnon-toxic pharmaceutically acceptable excipient which are suitable formanufacture of tablets are acceptable. These excipients may be, forexample, inert diluents, such as calcium or sodium carbonate, lactose,calcium or sodium phosphate; granulating and disintegrating agents, suchas maize starch, or alginic acid; binding agents, such as starch,gelatin or acacia; and lubricating agents, such as magnesium stearate,stearic acid or talc. Tablets may be uncoated or may be coated by knowntechniques including microencapsulation to delay disintegration andadsorption in the gastrointestinal tract and thereby provide a sustainedaction over a longer period. For example, a time delay material such asglyceryl monostearate or glyceryl distearate alone or with a wax may beemployed.

Formulations for oral use may be also presented as hard gelatin capsuleswhere the active ingredient is mixed with an inert solid diluent, forexample calcium phosphate or kaolin, or as soft gelatin capsules whereinthe active ingredient is mixed with water or an oil medium, such aspeanut oil, liquid paraffin or olive oil.

Aqueous suspensions contain the active materials in admixture withexcipients suitable for the manufacture of aqueous suspensions. Suchexcipients include a suspending agent, such as sodiumcarboxymethylcellulose, methylcellulose, hydroxypropyl methylcelluose,sodium alginate, polyvinylpyrrolidone, gum tragacanth and gum acacia,and dispersing or wetting agents such as a naturally-occurringphosphatide (e.g., lecithin), a condensation product of an alkyleneoxide with a fatty acid (e.g., polyoxyethylene stearate), a condensationproduct of ethylene oxide with a long chain aliphatic alcohol (e.g.,heptadecaethyleneoxycetanol), a condensation product of ethylene oxidewith a partial ester derived from a fatty acid and a hexitol anhydride(e.g., polyoxyethylene sorbitan monooleate). The aqueous suspension mayalso contain one or more preservatives such as ethyl or n-propylp-hydroxy-benzoate, one or more coloring agents, one or more flavoringagents and one or more sweetening agents, such as sucrose or saccharin.

Oil suspensions may be formulated by suspending the active ingredient ina vegetable oil, such as arachis oil, olive oil, sesame oil or coconutoil, or in a mineral oil such as liquid paraffin. The oral suspensionsmay contain a thickening agent, such as beeswax, hard paraffin or cetylalcohol. Sweetening agents, such as those set forth above, and flavoringagents may be added to provide a palatable oral preparation. Thesecompositions may be preserved by the addition of an antioxidant such asascorbic acid.

Dispersible powders and granules suitable for preparation of an aqueoussuspension by the addition of water provide the active ingredient inadmixture with a dispersing or wetting agent, a suspending agent, andone or more preservatives. Suitable dispersing or wetting agents andsuspending agents are exemplified by those disclosed above. Additionalexcipients, for example sweetening, flavoring and coloring agents, mayalso be present.

The pharmaceutical compositions may also be in the form of oil-in-wateremulsions. The oily phase may be a vegetable oil, such as olive oil orarachis oil, a mineral oil, such as liquid paraffin, or a mixture ofthese. Suitable emulsifying agents include naturally-occurring gums,such as gum acacia and gum tragacanth, naturally-occurring phosphatides,such as soybean lecithin, esters or partial esters derived from fattyacids and hexitol anhydrides, such as sorbitan monooleate, andcondensation products of these partial esters with ethylene oxide, suchas polyoxyethylene sorbitan monooleate. The emulsion may also containsweetening and flavoring agents. Syrups and elixirs may be formulatedwith sweetening agents, such as glycerol, sorbitol or sucrose. Suchformulations may also contain a demulcent, a preservative, a flavoringor a coloring agent.

The pharmaceutical compositions may be in the form of a sterileinjectable or intravenous preparations, such as a sterile injectableaqueous or oleaginous suspension. This suspension may be formulatedaccording to the known art using those suitable dispersing or wettingagents and suspending agents which have been mentioned above. Thesterile injectable or intravenous preparation may also be a sterileinjectable solution or suspension in a non-toxic parenterally acceptablediluent or solvent, such as a solution in 1,3-butane-dial or prepared asa lyophilized powder. Among the acceptable vehicles and solvents thatmay be employed are water, Ringer's solution and isotonic sodiumchloride solution. In addition, sterile fixed oils may conventionally beemployed as a solvent or suspending medium. For this purpose any blandfixed oil may be employed including synthetic mono- or diglycerides. Inaddition, fatty acids such as oleic acid may likewise be used in thepreparation of injectables.

The amount of active ingredient that may be combined with the carriermaterial to produce a single dosage form will vary depending upon thehost treated and the particular mode of administration. For example, atime-release formulation intended for oral administration to humans maycontain approximately 1 to 1000 mg of active material compounded with anappropriate and convenient amount of carrier material which may varyfrom about 5 to about 95% of the total compositions (weight:weight). Thepharmaceutical composition can be prepared to provide easily measurableamounts for administration. For example, an aqueous solution intendedfor intravenous infusion may contain from about 3 to 500 μg of theactive ingredient per milliliter of solution in order that infusion of asuitable volume at a rate of about 30 mL/hr can occur.

Formulations suitable for topical administration to the eye also includeeye drops wherein the active ingredient is dissolved or suspended in asuitable carrier, especially an aqueous solvent for the activeingredient. The active ingredient is preferably present in suchformulations in a concentration of 0.5 to 20%, advantageously 0.5 to10%, and particularly about 1.5% w/w.

Formulations suitable for topical administration in the mouth includelozenges comprising the active ingredient in a flavored basis, usuallysucrose and acacia or tragacanth; pastilles comprising the activeingredient in an inert basis such as gelatin and glycerin, or sucroseand acacia; and mouthwashes comprising the active ingredient in asuitable liquid carrier.

Formulations for rectal administration may be presented as a suppositorywith a suitable base comprising for example cocoa butter or asalicylate.

Formulations suitable for intrapulmonary or nasal administration have aparticle size for example in the range of 0.1 to 500 microns, such as0.5, 1, 30, 35 etc., which is administered by rapid inhalation throughthe nasal passage or by inhalation through the mouth so as to reach thealveolar sacs. Suitable formulations include aqueous or oily solutionsof the active ingredient. Formulations suitable for aerosol or drypowder administration may be prepared according to conventional methodsand may be delivered with other therapeutic agents such as compoundsheretofore used in the treatment or prophylaxis of Pneumovirinaeinfections as described below.

Another embodiments provides a novel, efficacious, safe, nonirritatingand physiologically compatible inhalable composition comprising acompound of Formula (I) or Formula (II), or a pharmaceuticallyacceptable salt thereof, suitable for treating Pneumovirinae infectionsand potentially associated bronchiolitis. Preferred pharmaceuticallyacceptable salts are inorganic acid salts including hydrochloride,hydrobromide, sulfate or phosphate salts as they may cause lesspulmonary irritation. Preferably, the inhalable formulation is deliveredto the endobronchial space in an aerosol comprising particles with amass median aerodynamic diameter (MMAD) between about 1 and about 5 μm.Preferably, the compound of Formula (I) or Formula (II) is formulatedfor aerosol delivery using a nebulizer, pressurized metered dose inhaler(pMDI), or dry powder inhaler (DPI).

Non-limiting examples of nebulizers include atomizing, jet, ultrasonic,pressurized, vibrating porous plate, or equivalent nebulizers includingthose nebulizers utilizing adaptive aerosol delivery technology (Denyer,J. Aerosol medicine Pulmonary Drug Delivery 2010, 23 Supp 1, S1-S10). Ajet nebulizer utilizes air pressure to break a liquid solution intoaerosol droplets. An ultrasonic nebulizer works by a piezoelectriccrystal that shears a liquid into small aerosol droplets. A pressurizednebulization system forces solution under pressure through small poresto generate aerosol droplets. A vibrating porous plate device utilizesrapid vibration to shear a stream of liquid into appropriate dropletsizes.

In a preferred embodiment, the formulation for nebulization is deliveredto the endobronchial space in an aerosol comprising particles with aMMAD predominantly between about 1 μm and about 5 μm using a nebulizerable to aerosolize the formulation of the compound of Formula (I) orFormula (II) into particles of the required MMAD. To be optimallytherapeutically effective and to avoid upper respiratory and systemicside effects, the majority of aerosolized particles should not have aMMAD greater than about 5 μm. If an aerosol contains a large number ofparticles with a MMAD larger than 5 μm, the particles are deposited inthe upper airways decreasing the amount of drug delivered to the site ofinflammation and bronchoconstriction in the lower respiratory tract. Ifthe MMAD of the aerosol is smaller than about 1 μm, then the particleshave a tendency to remain suspended in the inhaled air and aresubsequently exhaled during expiration.

When formulated and delivered according to the method herein, theaerosol formulation for nebulization delivers a therapeuticallyefficacious dose of the compound of Formula (I) or Formula (II) to thesite of Pneumovirinae infection sufficient to treat the Pneumovirinaeinfection. The amount of drug administered must be adjusted to reflectthe efficiency of the delivery of a therapeutically efficacious dose ofthe compound of Formula (I) or Formula (II). In a preferred embodiment,a combination of the aqueous aerosol formulation with the atomizing,jet, pressurized, vibrating porous plate, or ultrasonic nebulizerpermits, depending on the nebulizer, about, at least, 20, to about 90%,typically about 70% delivery of the administered dose of the compound ofFormula (I) or Formula (II) into the airways. In a preferred embodiment,at least about 30 to about 50% of the active compound is delivered. Morepreferably, about 70 to about 90% of the active compound is delivered.

In another embodiment, a compound of Formula (I) or Formula (II) or apharmaceutically acceptable salt thereof, is delivered as a dryinhalable powder. The compounds are administered endobronchially as adry powder formulation to efficacious deliver fine particles of compoundinto the endobronchial space using dry powder or metered dose inhalers.For delivery by DPI, the compound of Formula (I) or Formula (II) isprocessed into particles with, predominantly, MMAD between about 1 μmand about 5 μm by milling spray drying, critical fluid processing, orprecipitation from solution. Media milling, jet milling and spray-dryingdevices and procedures capable of producing the particle sizes with aMMAD between about 1 μm and about 5 μm are well known in the art. In oneembodiment, excipients are added to the compound of Formula (I) orFormula (II) before processing into particles of the required sizes. Inanother embodiment, excipients are blended with the particles of therequired size to aid in dispersion of the drug particles, for example byusing lactose as an excipient.

Particle size determinations are made using devices well known in theart. For example a multi-stage Anderson cascade impactor or othersuitable method such as those specifically cited within the USPharmacopoeia Chapter 601 as characterizing devices for aerosols withinmetered-dose and dry powder inhalers.

In another preferred embodiment, a compound of Formula (I) or Formula(II) is delivered as a dry powder using a device such as a dry powderinhaler or other dry powder dispersion devices. Non-limiting examples ofdry powder inhalers and devices include those disclosed in U.S. Pat. No.5,458,135; U.S. Pat. No. 5,740,794; U.S. Pat. No. 5,775,320; U.S. Pat.No. 5,785,049; U.S. Pat. No. 3,906,950; U.S. Pat. No. 4,013,075; U.S.Pat. No. 4,069,819; U.S. Pat. No. 4,995,385; U.S. Pat. No. 5,522,385;U.S. Pat. No. 4,668,218; U.S. Pat. No. 4,667,668; U.S. Pat. No.4,805,811 and U.S. Pat. No. 5,388,572. There are two major designs ofdry powder inhalers. One design is a metering device in which areservoir for the drug is place within the device and the patient adds adose of the drug into the inhalation chamber. The second design is afactory-metered device in which each individual dose has beenmanufactured in a separate container. Both systems depend on theformulation of the drug into small particles of MMAD from 1 μm and about5 μm and often involve co-formulation with larger excipient particlessuch as, but not limited to, lactose. Drug powder is placed in theinhalation chamber (either by device metering or by breakage of afactory-metered dosage) and the inspiratory flow of the patientaccelerates the powder out of the device and into the oral cavity.Non-laminar flow characteristics of the powder path cause theexcipient-drug aggregates to decompose, and the mass of the largeexcipient particles causes their impaction at the back of the throat,while the smaller drug particles are deposited deep in the lungs. Inpreferred embodiments, a compound of Formula (I) or Formula (II), or apharmaceutically acceptable salt thereof, is delivered as a dry powderusing either type of dry powder inhaler as described herein, wherein theMMAD of the dry powder, exclusive of any excipients, is predominantly inthe range of 1 μm to about 5 μm.

In another embodiment, a compound of Formula (I) or Formula (II) isdelivered as a dry powder using a metered dose inhaler. Non-limitingexamples of metered dose inhalers and devices include those disclosed inU.S. Pat. No. 5,261,538; U.S. Pat. No. 5,544,647; U.S. Pat. No.5,622,163; U.S. Pat. No. 4,955,371; U.S. Pat. No. 3,565,070; U.S. Pat.No. 3,361,306 and U.S. Pat. No. 6,116,234. In preferred embodiments, acompound of Formula (I) or Formula (II), or a pharmaceuticallyacceptable salt thereof, is delivered as a dry powder using a metereddose inhaler wherein the MMAD of the dry powder, exclusive of anyexcipients, is predominantly in the range of about 1-5 μm.

Formulations suitable for vaginal administration may be presented aspessaries, tampons, creams, gels, pastes, foams or spray formulationscontaining in addition to the active ingredient such carriers as areknown in the art to be appropriate.

Formulations suitable for parenteral administration include aqueous andnon-aqueous sterile injection solutions which may contain anti-oxidants,buffers, bacteriostats and solutes which render the formulation isotonicwith the blood of the intended recipient; and aqueous and non-aqueoussterile suspensions which may include suspending agents and thickeningagents.

The formulations are presented in unit-dose or multi-dose containers,for example sealed ampoules and vials, and may be stored in afreeze-dried (lyophilized) condition requiring only the addition of thesterile liquid carrier, for example water for injection, immediatelyprior to use. Extemporaneous injection solutions and suspensions areprepared from sterile powders, granules and tablets of the kindpreviously described. Preferred unit dosage formulations are thosecontaining a daily dose or unit daily sub-dose, as herein above recited,or an appropriate fraction thereof, of the active ingredient.

It should be understood that in addition to the ingredients particularlymentioned above the formulations may include other agents conventionalin the art having regard to the type of formulation in question, forexample those suitable for oral administration may include flavoringagents.

Further provided are veterinary compositions comprising at least oneactive ingredient as above defined together with a veterinary carriertherefor.

Veterinary carriers are materials useful for the purpose ofadministering the composition and may be solid, liquid or gaseousmaterials which are otherwise inert or acceptable in the veterinary artand are compatible with the active ingredient. These veterinarycompositions may be administered orally, parenterally or by any otherdesired route.

Compounds herein are used to provide controlled release pharmaceuticalformulations containing as active ingredient one or more of thecompounds (“controlled release formulations”) in which the release ofthe active ingredient are controlled and regulated to allow lessfrequency dosing or to improve the pharmacokinetic or toxicity profileof a given active ingredient.

Effective dose of active ingredient depends at least on the nature ofthe condition being treated, toxicity, whether the compound is beingused prophylactically (lower doses) or against an active viralinfection, the method of delivery, and the pharmaceutical formulation,and will be determined by the clinician using conventional doseescalation studies. It can be expected to be from about 0.0001 to about100 mg/kg body weight per day; typically, from about 0.01 to about 10mg/kg body weight per day; more typically, from about 0.01 to about 5mg/kg body weight per day; most typically, from about 0.05 to about 0.5mg/kg body weight per day. For example, the daily candidate dose for anadult human of approximately 70 kg body weight will range from 1 mg to1000 mg, preferably between 5 mg and 500 mg, and may take the form ofsingle or multiple doses.

Routes of Administration

One or more of the compounds (herein referred to as the activeingredients) are administered by any route appropriate to the conditionto be treated. Suitable routes include oral, rectal, nasal, pulmonary,topical (including buccal and sublingual), vaginal and parenteral(including subcutaneous, intramuscular, intravenous, intradermal,intrathecal and epidural), and the like. It will be appreciated that thepreferred route may vary with for example the condition of therecipient. An advantage of the compounds herein is that they are orallybioavailable and can be dosed orally.

Combination Therapy

Compositions are also used in combination with other active ingredients.For the treatment of Pneumovirinae virus infections, preferably, theother active therapeutic agent is active against Pneumovirinae virusinfections, particularly respiratory syncytial virus infections.Non-limiting examples of these other active therapeutic agents areribavirin, palivizumab, motavizumab, RSV-IGIV (RespiGam®), MEDI-557,A-60444 (also known as RSV604), MDT-637, BMS-433771, ALN-RSVO, ALX-0171and mixtures thereof.

Many of the infections of the Pneumovirinae viruses are respiratoryinfections. Therefore, additional active therapeutics used to treatrespiratory symptoms and sequelae of infection may be used incombination with the compounds of Formula (I) or Formula (II). Theadditional agents are preferably administered orally or by directinhalation. For example, other preferred additional therapeutic agentsin combination with the compounds of Formula (I) or Formula (II) for thetreatment of viral respiratory infections include, but are not limitedto, bronchodilators and corticosteroids.

Glucocorticoids, which were first introduced as an asthma therapy in1950 (Carryer, Journal of Allergy, 21, 282-287, 1950), remain the mostpotent and consistently effective therapy for this disease, althoughtheir mechanism of action is not yet fully understood (Morris, J.Allergy Clin. Immunol., 75 (1 Pt) 1-13, 1985). Unfortunately, oralglucocorticoid therapies are associated with profound undesirable sideeffects such as truncal obesity, hypertension, glaucoma, glucoseintolerance, acceleration of cataract formation, bone mineral loss, andpsychological effects, all of which limit their use as long-termtherapeutic agents (Goodman and Gilman, 10th edition, 2001). A solutionto systemic side effects is to deliver steroid drugs directly to thesite of inflammation. Inhaled corticosteroids (ICS) have been developedto mitigate the severe adverse effects of oral steroids. Non-limitingexamples of corticosteroids that may be used in combinations with thecompounds of Formula (I) or Formula (II) are dexamethasone,dexamethasone sodium phosphate, fluorometholone, fluorometholoneacetate, loteprednol, loteprednol etabonate, hydrocortisone,prednisolone, fludrocortisones, triamcinolone, triamcinolone acetonide,betamethasone, beclomethasone diproprionate, methylprednisolone,fluocinolone, fluocinolone acetonide, flunisolide,fluocortin-21-butylate, flumethasone, flumetasone pivalate, budesonide,halobetasol propionate, mometasone furoate, fluticasone propionate,ciclesonide; or a pharmaceutically acceptable salts thereof.

Other anti-inflamatory agents working through anti-inflamatory cascademechanisms are also useful as additional therapeutic agents incombination with the compounds of Formula (I) or Formula (II) for thetreatment of viral respiratory infections. Applying “anti-inflammatorysignal transduction modulators” (referred to in this text as AISTM),like phosphodiesterase inhibitors (e.g. PDE-4, PDE-5, or PDE-7specific), transcription factor inhibitors (e.g. blocking NFκB throughIKK inhibition), or kinase inhibitors (e.g. blocking P38 MAP, JNK, PI3K,EGFR or Syk) is a logical approach to switching off inflammation asthese small molecules target a limited number of common intracellularpathways—those signal transduction pathways that are critical points forthe anti-inflammatory therapeutic intervention (see review by P. J.Barnes, 2006). These non-limiting additional therapeutic agents include:5-(2,4-Difluoro-phenoxy)-1-isobutyl-1H-indazole-6-carboxylic acid(2-dimethylamino-ethyl)-amide (P38 Map kinase inhibitor ARRY-797);3-Cyclopropylmethoxy-N-(3,5-dichloro-pyridin-4-yl)-4-difluorormethoxy-benzamide(PDE-4 inhibitor Roflumilast);4-[2-(3-cyclopentyloxy-4-methoxyphenyl)-2-phenyl-ethyl]-pyridine (PDE-4inhibitor CDP-840);N-(3,5-dichloro-4-pyridinyl)-4-(difluoromethoxy)-8-[(methylsulfonyl)amino]-1-dibenzofurancarboxamide(PDE-4 inhibitor Oglemilast);N-(3,5-Dichloro-pyridin-4-yl)-2-[1-(4-fluorobenzyl)-5-hydroxy-1H-indol-3-yl]-2-oxo-acetamide(PDE-4 inhibitor AWD 12-281);8-Methoxy-2-trifluoromethyl-quinoline-5-carboxylic acid(3,5-dichloro-1-oxy-pyridin-4-yl)-amide (PDE-4 inhibitor Sch 351591);4-[5-(4-Fluorophenyl)-2-(4-methanesulfinyl-phenyl)-1H-imidazol-4-yl]-pyridine(P38 inhibitor SB-203850);4-[4-(4-Fluoro-phenyl)-1-(3-phenyl-propyl)-5-pyridin-4-yl-1H-imidazol-2-yl]-but-3-yn-1-ol(P38 inhibitor RWJ-67657);4-Cyano-4-(3-cyclopentyloxy-4-methoxy-phenyl)-cyclohexanecarboxylic acid2-diethylamino-ethyl ester (2-diethyl-ethyl ester prodrug of Cilomilast,PDE-4 inhibitor);(3-Chloro-4-fluorophenyl)-[7-methoxy-6-(3-morpholin-4-yl-propoxy)-quinazolin-4-yl]-amine(Gefitinib, EGFR inhibitor); and4-(4-Methyl-piperazin-1-ylmethyl)-N-[4-methyl-3-(4-pyridin-3-yl-pyrimidin-2-ylamino)-phenyl]-benzamide(Imatinib, EGFR inhibitor).

Combinations comprising inhaled β2-adrenoreceptor agonistbronchodilators such as formoterol, albuterol or salmeterol with thecompounds of Formula (I) or Formula (II) are also suitable, butnon-limiting, combinations useful for the treatment of respiratory viralinfections.

Combinations of inhaled β2-adrenoreceptor agonist bronchodilators suchas formoterol or salmeterol with ICS's are also used to treat both thebronchoconstriction and the inflammation (Symbicort® and Advair®,respectively). The combinations comprising these ICS andβ2-adrenoreceptor agonist combinations along with the compounds ofFormula (I) or Formula (II) are also suitable, but non-limiting,combinations useful for the treatment of respiratory viral infections.

For the treatment or prophylaxis of pulmonary broncho-constriction,anticholinergics are of potential use and, therefore, useful as anadditional therapeutic agents in combination with the compounds ofFormula (I) or Formula (II) for the treatment of viral respiratoryinfections. These anticholinergics include, but are not limited to,antagonists of the muscarinic receptor (particularly of the M3 subtype)which have shown therapeutic efficacy in man for the control ofcholinergic tone in COPD (Witek, 1999);1-{4-Hydroxy-1-[3,3,3-tris-(4-fluoro-phenyl)-propionyl]-pyrrolidine-2-carbonyl}-pyrrolidine-2-carboxylicacid (1-methyl-piperidin-4-ylmethyl)-amide;3-[3-(2-Diethylamino-acetoxy)-2-phenyl-propionyloxy]-8-isopropyl-8-methyl-8-azonia-bicyclo[3.2.1]octane(Ipratropium-N,N-diethylglycinate);1-Cyclohexyl-3,4-dihydro-1H-isoquinoline-2-carboxylic acid1-aza-bicyclo[2.2.2]oct-3-yl ester (Solifenacin);2-Hydroxymethyl-4-methanesulfinyl-2-phenyl-butyric acid1-aza-bicyclo[2.2.2]oct-3-yl ester (Revatropate);2-{1-[2-(2,3-Dihydro-benzofuran-5-yl)-ethyl]-pyrrolidin-3-yl}-2,2-diphenyl-acetamide(Darifenacin); 4-Azepan-1-yl-2,2-diphenyl-butyramide (Buzepide);7-[3-(2-Diethylamino-acetoxy)-2-phenyl-propionyloxy]-9-ethyl-9-methyl-3-oxa-9-azonia-tricyclo[3.3.1.02,4]nonane(Oxitropium-N,N-diethylglycinate);7-[2-(2-Diethylamino-acetoxy)-2,2-di-thiophen-2-yl-acetoxy]-9,9-dimethyl-3-oxa-9-azonia-tricyclo[3.3.1.02,4]nonane(Tiotropium-N,N-diethylglycinate); Dimethylamino-acetic acid2-(3-diisopropylamino-1-phenyl-propyl)-4-methyl-phenyl ester(Tolterodine-N,N-dimethylglycinate);3-[4,4-Bis-(4-fluoro-phenyl)-2-oxo-imidazolidin-1-yl]-1-methyl-1-(2-oxo-2-pyridin-2-yl-ethyl)-pyrrolidinium;1-[1-(3-Fluoro-benzyl)-piperidin-4-yl]-4,4-bis-(4-fluoro-phenyl)-imidazolidin-2-one;1-Cyclooctyl-3-(3-methoxy-1-aza-bicyclo[2.2.2]oct-3-yl)-1-phenyl-prop-2-yn-1-ol;3-[2-(2-Diethylamino-acetoxy)-2,2-di-thiophen-2-yl-acetoxy]-1-(3-phenoxy-propyl)-1-azonia-bicyclo[2.2.2]octane(Aclidinium-N,N-diethylglycinate); or(2-Diethylamino-acetoxy)-di-thiophen-2-yl-acetic acid1-methyl-1-(2-phenoxy-ethyl)-piperidin-4-yl ester.

The compounds of Formula (I) or Formula (II) may also be combined withmucolytic agents to treat both the infection and symptoms of respiratoryinfections. A non-limiting example of a mucolytic agent is ambroxol.Similarly, the compounds of Formula (I) or Formula (II) may be combinedwith expectorants to treat both the infection and symptoms ofrespiratory infections. A non-limiting example of an expectorant isguaifenesin.

Nebulized hypertonic saline is used to improve immediate and long-termclearance of small airways in patients with lung diseases (Kuzik, J.Pediatrics 2007, 266). The compounds of Formula (I) or Formula (II) mayalso be combined with nebulized hypertonic saline particularly when thePneumovirinae virus infection is complicated with bronchiolitis. Thecombination of the compounds of Formula (I) or Formula (II) withhypertonic saline may also comprise any of the additional agentsdiscussed above. In one embodiment, nebulized about 3% hypertonic salineis used.

It is also possible to combine any compound with one or more additionalactive therapeutic agents in a unitary dosage form for simultaneous orsequential administration to a patient. The combination therapy may beadministered as a simultaneous or sequential regimen. When administeredsequentially, the combination may be administered in two or moreadministrations.

Co-administration of a compound herein with one or more other activetherapeutic agents generally refers to simultaneous or sequentialadministration of a compound and one or more other active therapeuticagents, such that therapeutically effective amounts of the compound andone or more other active therapeutic agents are both present in the bodyof the patient.

Co-administration includes administration of unit dosages of thecompounds before or after administration of unit dosages of one or moreother active therapeutic agents, for example, administration of thecompounds within seconds, minutes, or hours of the administration of oneor more other active therapeutic agents. For example, a unit dose of acompound can be administered first, followed within seconds or minutesby administration of a unit dose of one or more other active therapeuticagents. Alternatively, a unit dose of one or more other therapeuticagents can be administered first, followed by administration of a unitdose of a compound within seconds or minutes. In some cases, it may bedesirable to administer a unit dose of a compound first, followed, aftera period of hours (e.g., 1-12 hours), by administration of a unit doseof one or more other active therapeutic agents. In other cases, it maybe desirable to administer a unit dose of one or more other activetherapeutic agents first, followed, after a period of hours (e.g., 1-12hours), by administration of a unit dose of a compound herein.

The combination therapy may provide “synergy” and “synergistic”, i.e.the effect achieved when the active ingredients used together is greaterthan the sum of the effects that results from using the compoundsseparately. A synergistic effect may be attained when the activeingredients are: (1) co-formulated and administered or deliveredsimultaneously in a combined formulation; (2) delivered by alternationor in parallel as separate formulations; or (3) by some other regimen.When delivered in alternation therapy, a synergistic effect may beattained when the compounds are administered or delivered sequentially,e.g. in separate tablets, pills or capsules, or by different injectionsin separate syringes. In general, during alternation therapy, aneffective dosage of each active ingredient is administered sequentially,i.e. serially, whereas in combination therapy, effective dosages of twoor more active ingredients are administered together. A synergisticanti-viral effect denotes an antiviral effect which is greater than thepredicted purely additive effects of the individual compounds of thecombination.

In still yet another embodiment, the present application provides amethod of treating Pneumovirinae virus infection in a human, the methodcomprising administering to the human a therapeutically effective amountof a compound of Formula (I), or a pharmaceutically acceptable salt,solvate, and/or ester thereof. Also provided are separate methods oftreating Pneumovirinae virus infection in a human, each comprisingadministering to the human a therapeutically effective apharmaceutically effective amount of a compound of Formula (II) or oneof the specific compounds of the examples herein, or a pharmaceuticallyacceptable salt, solvate, and/or ester thereof, and a pharmaceuticallyacceptable carrier or excipient.

In another embodiment, provided is a method of treating a Pneumovirinaeinfection in a human by administering to the human a therapeuticallyeffective amount of a racemate, enantiomer, diastereomer, tautomer,polymorph, pseudopolymorph, amorphous form, hydrate or solvate of acompound of a compound of Formula (I), or a pharmaceutically acceptablesalt or ester thereof.

Further provided are separate methods of treating a Pneumovirinaeinfection in a human in need thereof, each method comprisingadministering to the human a therapeutically effective amount of aracemate, enantiomer, diastereomer, tautomer, polymorph,pseudopolymorph, amorphous form, hydrate or solvate of a compound ofFormula (II) or one of the specific compounds of the examples herein, ora pharmaceutically acceptable salt, solvate, and/or ester thereof.

In still yet another embodiment, the present application provides for amethod of treating human respiratory syncytial virus infection in ahuman, the method comprising administering to the human atherapeutically effective amount of a compound of Formula (I), or apharmaceutically acceptable salt, solvate, and/or ester thereof.

In still yet another embodiment, the present application provides for amethod of treating human respiratory syncytial virus infection in ahuman, the method comprising administering to the human atherapeutically effective amount of a compound of Formula (I), or apharmaceutically acceptable salt, solvate, and/or ester thereof, and atleast one additional active therapeutic agent.

Further provided are separate methods of treating a human respiratorysyncytial virus infection in a human in need thereof, each methodcomprising administering to the human a therapeutically effective amountof a compound of Formula (II) or one of the specific compounds of theexamples herein, or a pharmaceutically acceptable salt, solvate, and/orester thereof.

Also provided are separate methods of treating a human respiratorysyncytial virus infection in a human in need thereof, each methodcomprising administering to the human a therapeutically effective amountof a compound of Formula (II) or one of the specific compounds of theexamples herein, or a pharmaceutically acceptable salt, solvate, and/orester thereof, and at least one additional active therapeutic agent.

Also provided are separate methods of treating a human respiratorysyncytial virus infection in a human in need thereof, wherein the humanis also experiencing bronchiolitis, each method comprising administeringto the human a therapeutically effective amount of a compound of Formula(I), Formula (II), or one of the specific compounds of the examplesherein, or a pharmaceutically acceptable salt, solvate, and/or esterthereof.

Also provided are separate methods of treating a human respiratorysyncytial virus infection in a human in need thereof, wherein the humanis also experiencing pneumonia, each method comprising administering tothe human a therapeutically effective amount of a compound of Formula(I), Formula (II), or one of the specific compounds of the examplesherein, or a pharmaceutically acceptable salt, solvate, and/or esterthereof.

Also provided are separate methods of improving respiratory symptoms ina human experiencing a human respiratory syncytial virus infection, eachmethod comprising administering to the human a therapeutically effectiveamount of a compound of Formula (I), Formula (II), or one of thespecific compounds of the examples herein, or a pharmaceuticallyacceptable salt, solvate, and/or ester thereof.

Respiratory symptoms in a human experiencing a respiratory syncytialvirus infection may include congested or runny nose, coughing, wheezing,sneezing, rapid breathing or difficulty breathing, apnea, bronchiolitis,and pneumonia.

Also provided is an embodiment comprising the use of a compound ofFormula (I), or a pharmaceutically acceptable salt, solvate, and/orester thereof, for the manufacture of a medicament for the treatment ofa Pneumovirinae virus infection or a respiratory syncytial virusinfection.

Also provided is an embodiment comprising the use of a compound ofFormula (H) or one of the specific compounds of the examples herein, ora pharmaceutically acceptable salt, solvate, and/or ester thereof, forthe manufacture of a medicament for the treatment of a Pneumovirinaevirus infection or a respiratory syncytial virus infection.

Also provided is a pharmaceutical formulation comprising apharmaceutically effective amount of a compound of Formula (I), or apharmaceutically acceptable salt, solvate, and/or ester thereof, and apharmaceutically acceptable carrier or excipient. Further provided is apharmaceutical formulation comprising a pharmaceutically effectiveamount of a compound of Formula (II) or one of the specific compounds ofthe examples herein, or a pharmaceutically acceptable salt, solvate,and/or ester thereof, and a pharmaceutically acceptable carrier orexcipient.

Also provided is a pharmaceutical formulation comprising apharmaceutically effective amount of a compound of Formula (I), or apharmaceutically acceptable salt, solvate, and/or ester thereof, and apharmaceutically acceptable carrier or excipient and a pharmaceuticallyeffective amount of at least one additional active therapeutic agent.Further provided is a pharmaceutical formulation comprising apharmaceutically effective amount of a compound of Formula (II) or oneof the specific compounds of the examples herein, or a pharmaceuticallyacceptable salt, solvate, and/or ester thereof, and a pharmaceuticallyacceptable carrier or excipient and a pharmaceutically effective amountof at least one additional active therapeutic agent.

Also provided are separate embodiments comprising a compound of Formula(I), Formula (II), or one of the specific compounds of the examplesherein, or a pharmaceutically acceptable salt, solvate, and/or esterthereof, for use in the treatment of a Pneumovirinae virus infection ora respiratory syncytial virus infection in a human.

Also provided are separate embodiments comprising a compound of Formula(I), Formula (II) or one of the specific compounds of the examplesherein, or a pharmaceutically acceptable salt, solvate, and/or esterthereof, for use as a medicament.

Also provided are separate embodiments comprising a method formanufacturing a medicament intended for treatment of a Pneumovirinaevirus infection or a respiratory syncytial virus infection in a human,characterised in that a compound of Formula (I), Formula (II), or one ofthe specific compounds of the examples herein, or a pharmaceuticallyacceptable salt, solvate, and/or ester thereof, is used.

Also provided is a compound of Formula (I), or a pharmaceuticallyacceptable salt, solvate, and/or ester thereof, for the treatment of aPneumovirinae virus infection or a respiratory syncytial virus infectionin a human.

Also provided are separate embodiments comprising that a compound ofFormula (II) or one of the specific compounds of the examples herein, ora pharmaceutically acceptable salt, solvate, and/or ester thereof, forthe treatment of a Pneumovirinae virus infection or a respiratorysyncytial virus infection in a human.

Further provided is a compound as described in this specification. Alsoprovided is a pharmaceutical composition as described in thisspecification. Also provided is a method of using a compound of Formula(I), as described in this specification. Further provided is a method ofmaking a compound of Formula (I), as described in this specification.

Metabolites of the Compounds

Also falling within the scope herein are the in vivo metabolic productsof the compounds described herein, to the extent such products are noveland unobvious over the prior art. Such products may result for examplefrom the oxidation, reduction, hydrolysis, amidation, esterification andthe like of the administered compound, primarily due to enzymaticprocesses. Accordingly, included are novel and unobvious compoundsproduced by a process comprising contacting a compound with a mammal fora period of time sufficient to yield a metabolic product thereof. Suchproducts typically are identified by preparing a radiolabelled (e.g. ¹⁴Cor ³H) compound, administering it parenterally in a detectable dose(e.g. greater than about 0.5 mg/kg) to an animal such as rat, mouse,guinea pig, monkey, or to man, allowing sufficient time for metabolismto occur (typically about 30 seconds to 30 hours) and isolating itsconversion products from the urine, blood or other biological samples.These products are easily isolated since they are labeled (others areisolated by the use of antibodies capable of binding epitopes survivingin the metabolite). The metabolite structures are determined inconventional fashion, e.g. by MS or NMR analysis. In general, analysisof metabolites is done in the same way as conventional drug metabolismstudies well-known to those skilled in the art. The conversion products,so long as they are not otherwise found in vivo, are useful indiagnostic assays for therapeutic dosing of the compounds even if theypossess no HSV antiviral activity of their own.

Recipes and methods for determining stability of compounds in surrogategastrointestinal secretions are known. Compounds are defined herein asstable in the gastrointestinal tract where less than about 50 molepercent of the protected groups are deprotected in surrogate intestinalor gastric juice upon incubation for 1 hour at 37° C. Simply because thecompounds are stable to the gastrointestinal tract does not mean thatthey cannot be hydrolyzed in vivo. The prodrugs typically will be stablein the digestive system but may be substantially hydrolyzed to theparental drug in the digestive lumen, liver, lung or other metabolicorgan, or within cells in general. As used herein, a prodrug isunderstood to be a compound that is chemically designed to efficientlyliberate the parent drug after overcoming biological barriers to oraldelivery.

Abbreviations

Certain abbreviations and acronyms are used in describing theexperimental details. Although most of these would be understood by oneskilled in the art, Table 1 contains a list of many of theseabbreviations and acronyms.

TABLE 1 List of abbreviations and acronyms. Abbreviation Meaning Acacetate ACN acetonitrile AIBN azobisisobutyronitrile Bn benzyl Bu butylBz benzoyl BzCl benzoyl chloride CDI 1,1′-carbonyldiimidazole DASTdiethylaminosulfur trifluoride DCE 1,2-dichloroethane DCMdichloromethane DMAP 4-dimethylamiopyridine DMDO dimethydioxirane DMSOdimethylsulfoxide DMF dimethylformamide DMTrCl4,4′-dimethoxytritylchloride DMTr 4,4′-dimethoxytrityl EDClN-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride Et ethylImid imidazole KOtBu potassium tert-butoxide LC liquid chromatographyMCPBA meta-chloroperbenzoic acid Me methyl m/z mass to charge ratio MSor ms mass spectrum NIS N-iodosuccinimide NMP N-methyl-2-pyrrolidone Phphenyl Ph₃P triphenylphosphine PMB para-methoxybenzyl PMBClpara-methoxybenzyl chloride PhOC(S)Cl phenylchlorothionoformate(PhO)₃PMel methyltriphenoxyphosphonium iodide Pyr pyridine RT roomtemperature TBAF tetrabutylammonium flouride TBS tert-butyldimethylsilylTBSCl tert-Butyldimethylsilyl chloride TMSN₃ trimethylsilyl azide TEAtriethylamine TES triethysilane TFA trifluoroacetic acid THFtetrahydrofuran TMS trimethylsilyl TMSCl trimethylsilyl chloride Ts4-toluenesulfonyl TsOH tosylic acid δ parts per million referenced toresidual non-deuterated solvent peak

General Schemes

Scheme 1 shows a general synthesis of intermediates beginning with aniodination reaction (e.g. NIS) to generate nucleobase S1 b.

Scheme 2 shows a general synthesis of intermediates beginning with afluorination reaction (e.g. HBF₄, NaNO₂) in a manner similar to thatdescribed in WO2012037038A1 to afford intermediate S2b. Intermediate S2bcan then be iodinated (e.g. NIS) to generate nucleobase S2c.

Scheme 3 shows a general synthesis of compounds beginning with alithium-halogen exchange (e.g. n-BuLi, [—CH₂SiMe₂Cl]₂) reaction with anappropriate nucleobase Sib, followed by addition to the lactone S3a.Reduction of the pendant 1′ hydroxyl group under Lewis acidic conditions(e.g. BF₃.Et₂O, Et₃SiH) generates intermediate S3c. Intermediate S3c canfirst be protected (e.g. BzCl, Pyr; NH₄OH) at the nitrogenfunctionality, and the benzyl groups can then be removed under reducingconditions (e.g. HCO₂H, Pd/C, BCl₃, BBr₃) to afford intermediate S3d. Asequence involving first selective 5′ hydroxyl protection (e.g. DMTrCl),then 2′ and 3′ hydroxyl protection (e.g. TBSCl), followed by selectiveremoval of the 5′ hydroxyl protecting group under acidic conditions(e.g. TsOH) furnishes intermediate S3e. The 5′ hydroxyl group can thenbe converted to the corresponding iodide (e.g. (PhO)₃PMel), which isthen exposed to basic conditions (i.e. KOtBu) to effect an eliminationreaction generating intermediate S3f. Oxidation of the olefin S3f (e.g.DMDO) followed by treatment with an appropriate nucleophile (e.g. TMSCN)under Lewis acidic conditions (e.g. InBr₃) and removal of the hydroxylprotecting groups (e.g. CsF) affords intermediate S3g. Removal of thenitrogen protecting group (e.g. NH₂Me) yields the final compounds of thetype S3h.

Scheme 4 shows a general synthesis of compounds beginning with oxidationof the olefin S3f (e.g. DMDO) followed by treatment with an appropriatenucleophile (e.g. TMSN₃) under Lewis acidic conditions (e.g. InBr₃) in amanner similar to that described in J. Med. Chem. 2007, 50, 5463-5470.Removal of the hydroxyl protecting groups (e.g. CsF) then affordsintermediate S4a. Removal of the nitrogen protecting group (e.g. NH₂Me)yields the final compounds of the type S4b.

Scheme 5 shows a general synthesis of compounds beginning with oxidationof the olefin S3f (e.g. DMDO) in the presence of the appropriate alcoholHOR^(a) followed by removal of the hydroxyl protecting groups (e.g. CsF)to afford intermediate S5a. Removal of the nitrogen protecting group(e.g. NH₂Me) yields the final compounds of the type S5b.

Scheme 6 shows a general synthesis of compounds beginning with oxidationof the olefin S3f (e.g. DMDO) followed by treatment with an appropriatenucleophile (e.g. (HC≡C)₃Al) in a manner similar to that described inNucleosides, Nucleotides, and Nucleic Acids 2005, 24, 343-347. Removalof the hydroxyl protecting groups (e.g. CsF) then affords intermediateS6a. Removal of the nitrogen protecting group (e.g. NH₂Me) yields thefinal compounds of the type S6b. Elaboration of the final compoundthrough hydrogenation conditions (e.g. H₂, Pd/C or Lindlar's conditions)can selectively afford the final compounds of the type S6c and S6drespectively. Elaboration of the final compound S6d throughcyclopropanation conditions (e.g. CH₂N₂) can yield the final compoundsof the type S6e.

Scheme 7 shows a general synthesis of compounds beginning with asynthetic sequence to protect the nitrogen (e.g. TMSCl, Pyr; BzCl, Pyr;NH₄OH) of intermediate S7a, synthesized in a similar manner as describedin WO2012037038A1. Selective protection of the 5′ hydroxyl group (e.g.DMTrCl) then generates intermediate S7b. Protection of the 2′ hydroxylgroup (e.g. TBSCl) followed by removal of the 5′ hydroxyl group underacidic conditions (e.g. TsOH) furnishes intermediate S7e. Conversion ofthe 5′ hydroxyl group to the aldehyde under oxidative conditions (e.g.EDCl.HCl, Pyr, TFA, DMSO) followed by condensation of the correspondingenolate with formaldehyde and reduction (e.g. NaBH₄) yields intermediateS7f. Sequential selective protection of the hydroxyl moieties withorthogonal protecting groups (e.g. DMTrCl and TBSCl) followed by removalof the more labile protecting group under acidic conditions (e.g. TsOH)then affords intermediate S7g. Conversion of the hydroxyl group to thealdehyde under oxidative conditions (e.g. EDCl.HCl, Pyr, TFA, DMSO)generates intermediate S7h. Elaboration of the aldehyde S7h to thehalo-olefin intermediate S7i can be effected under Wittig olefinationconditions (e.g. [Ph₃PCH₂Br]⁺Br⁻, KOtBu). An elimination reaction underbasic conditions (e.g. KOtBu) generates the alkyne, and removal of thehydroxyl protecting groups (e.g. TBAF) and nitrogen protecting group(e.g. NH₄OH) yields the final compounds of the type S7j.

Scheme 8 shows a general synthesis of compounds beginning with oximeformation (e.g. NH₂OH.HCl), followed by conversion of the oxime to anitrile group (e.g. CDI). Removal of the nitrogen protecting group (e.g.NH₄OH), and hydroxyl protecting groups (e.g. HF.Pyr) then yields thefinal compounds of the type S8a.

Scheme 9 shows a general synthesis of compounds beginning withelaboration of the aldehyde S7h to the olefin with Wittig olefinationconditions (e.g. [Ph₃PCH₃]⁺Br⁻, KOtBu). Removal of the hydroxylprotecting groups (e.g. TBAF), and nitrogen protecting group (e.g.NH₄OH) yields the final compounds of the type S9a. Reducing conditions(e.g. H₂, Pd/C) then can generate the final compounds of the type S9b,and cyclopropanation conditions (e.g. CH₂N₂) can generate the finalcompounds of the type S9c.

Scheme 10 shows a general synthesis of compounds beginning with an Appelreaction (e.g. Ph₃P, CCl₄) to convert the hydroxyl group into achloride. Removal of the hydroxyl protecting groups (e.g. TBAF), andnitrogen protecting group (e.g. NH₄OH) yields the final compounds of thetype S10a.

Scheme 11 shows a general synthesis of compounds beginning withprotection of the free hydroxyl group of intermediate S7g with a labileprotecting group (e.g. PMBCl, K₂CO₃). Selective removal of the 2′ and 5′silyloxy protecting groups (e.g. TBAF), followed by reprotection withrobust protecting groups (e.g. BnBr, NaH), and removal of the labilehydroxyl protecting group under acidic conditions (e.g. AcOH) affordsintermediate S11a. Conversion of the hydroxyl group to the fluorine(e.g. DAST) followed by removal of the hydroxyl protecting groups (e.g.BBr₃), and nitrogen protecting group (e.g. NH₄OH) yields the finalcompounds of the type S11b.

Scheme 12 shows a general synthesis of compounds beginning withconversion of the 5′ hydroxyl group to the corresponding iodide (e.g.(PhO)₃PMel), which is then treated with basic conditions (i.e. KOtBu) toeffect an elimination reaction generating intermediate S12a. Oxidationof the olefin S12a (e.g. DMDO) followed by treatment with an appropriatenucleophile (e.g. TMSN₃) under Lewis acidic conditions (e.g. SnCl₄) in amanner similar to that described in J. Med. Chem. 2007, 50, 5463-5470,and removal of the hydroxyl protecting groups (e.g. CsF) and nitrogenprotecting group (e.g. NH₄OH) yields the final compounds of the typeS12b.

Scheme 13 shows a general synthesis of compounds beginning withoxidation of the olefin S12a (e.g. DMDO) in the presence of theappropriate alcohol HOW and removal of the hydroxyl protecting groups(e.g. CsF). Removal of the nitrogen protecting group (e.g. NH₂Me) yieldsthe final compounds of the type S13a.

Scheme 14 shows a general synthesis of compounds beginning with xanthateformation (e.g. PhOC(S)Cl, DMAP) followed by a Barton-McCombiedeoxygenation reaction (e.g. (TMS)₃SiH, AIBN) to generate intermediateS14a. Removal of the hydroxyl protecting groups (e.g. TBAF), andnitrogen protecting group (e.g. NH₄OH) yields the final compounds of thetype S14b.

Scheme 15 shows a general synthesis of compounds beginning withintermediate S15a prepared in a manner similar to that described inBiosci. Biotech. Biochem. 1993, 57, 1433-1438. Removal of the acetateprotecting groups using hydrolytic conditions (e.g. K₂CO₃, MeOH),followed by chemoselective oxidation conditions (e.g. NIS, Bu₄NI), andprotection of the 2′ hydroxyl group (e.g. BnBr, Ag₂O) generatesintermediate S15b. Lithium-halogen exchange (e.g. n-BuLi,[—CH₂SiMe₂Cl]₂) with an appropriate nucleobase S3b and addition to thelactone S15b, followed by reduction of the 1′ hydroxyl group under Lewisacidic conditions (e.g. BF₃.Et₂O, Et₃SiH), and deprotection (e.g. H₂, Pdblack) yields the final compounds of the type S15c.

Scheme 16 shows a general synthesis of compounds beginning withconversion of the 5′ hydroxyl group to the aldehyde under oxidativeconditions (e.g. EDCl.HCl, Pyr, TFA, DMSO) followed by condensation ofthe corresponding enolate with formaldehyde and reduction (e.g. NaBH₄)to yields intermediate S16a. Sequential selective protection of thehydroxyl moieties with orthogonal protecting groups (e.g. DMTrCl andTBSCl) followed by removal of the more labile protecting group underacidic conditions (e.g. TsOH) then affords intermediate S16b. An Appelreaction (e.g. Ph₃P, CCl₄) then can convert the hydroxyl group into achloride, and removal of the hydroxyl protecting groups (e.g. TBAF), andnitrogen protecting group (e.g. NH₄OH) yields the final compounds of thetype S16c.

Scheme 17 shows a general synthesis of compounds beginning withprotection of the free hydroxyl group of intermediate S16b with a labileprotecting group (e.g. PMBCl, K₂CO₃). Selective removal of the 2′, 3′,and 5′ silyloxy protecting groups (e.g. TBAF), followed by reprotectionof with robust protecting groups (e.g. BnBr, NaH), and removal of thelabile hydroxyl protecting group under acidic conditions (e.g. AcOH)affords intermediate S17a. Conversion of the hydroxyl group to thefluorine (e.g. DAST) followed by removal of the hydroxyl protectinggroups (e.g. BBr₃), and nitrogen protecting group (e.g. NH₄OH) yieldsthe final compounds of the type S17b.

Scheme 18 shows a general synthesis of compounds through appropriateelectrophilic halogenation reactions of intermediate S18a to afford thefinal compounds of the type S18b (e.g. NCS), S18c (e.g. NIS), and S18d(e.g. Selectfluor).

Scheme 19 shows a general synthesis of compounds beginning with across-coupling reaction (e.g. Zn(CN)₂, Pd(PtBu)₃) to yield the finalcompounds of the type S19a. Compound S19a can then be elaborated througha hydrolysis reaction of the nitrile (e.g. H₂O₂, NH₄OH, H₂O) to affordcompounds of the type S19b.

Scheme 20 shows a general synthesis of compounds beginning with aSonogashira reaction (e.g. CuI, PdCl₂(PPh₃)₂) to yield the finalcompounds of the type S20a.

Scheme 21 shows a general synthesis of compounds beginning with across-coupling reaction (e.g. Pd(dppf)Cl₂, Cs₂CO₃) to yield the finalcompounds of the type S21a.

Scheme 22 shows a general synthesis of compounds involving synthesis ofphosphorylated analogs of the type S22b.

Scheme 23 shows a general synthesis of compounds involving synthesis ofphosphorylated analogs of the type S23b.

Scheme 24 shows a general synthesis of compounds involving synthesis ofphosphorylated analogs of the type S24b.

EXPERIMENTALS

Intermediate 1b

To a solution of intermediate 1a (50 mg, 373 mmol) in DMF (1 mL) wascharged N-iodosuccinimide (84 mg, 373 mmol) as a solid at RT. After 1.5h, the reaction mixture was diluted 1M NaOH solution (10 mL), and theresulting slurry was stirred at RT. After 1 h, the solids were collectedby vacuum filtration and dried under reduced pressure to affordintermediate 1b.

¹H NMR (400 MHz, DMSO-d₆) δ 7.89 (s, 1H), 7.78 (br-s, 1H), 6.98 (d,J=4.4 Hz, 1H), 6.82 (d, J=4.4 Hz, 1H), 3.30 (br-s, 1H).

LC/MS: t_(R)=1.21 min, MS m/z=261.02 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6 mm

Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05 min 100% ACN,3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2 μl/min.

HPLC: t_(r)=1.536 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

Intermediate1d—(2S,3R,4R,5R)-2-(4-aminopyrrolo[1,2-f][1,2,4]triazin-7-yl)-3,4-bis(benzyloxy)-5-(benzyloxymethyl)tetrahydrofuran-2-ol

n-Butyllithium (2.5M in hexanes, 34.4 mL, 86.0 mmol) was added rapidlyto a suspension of 7-iodopyrrolo[1,2-f][1,2,4]triazin-4-amine 1b (6.84g, 26.3 mmol) and 1,2-bis(chlorodimethylsilyl)ethane (5.66 g, 26.3 mmol)in THF (200 mL) at −78° C. under an argon atmosphere. Over the course ofthe addition the internal temperature of the reaction mixture rose to−40.5° C., and the reaction mixture became a clear brown solution. After15 min, a solution of(3R,4R,5R)-3,4-bis(benzyloxy)-5-(benzyloxymethyl)dihydrofuran-2(3H)-one(1c, Purchased from Carbosynth, 10 g, 23.9 mmol) in tetrahydrofuran (40mL) precooled to −78° C., was added rapidly via cannula. After 1 h, thereaction mixture was quenched with acetic acid (15 mL), and theresulting mixture was allowed to warm to RT. The resulting mixture wasdiluted with ethyl acetate (800 mL) and was washed with saturatedaqueous sodium bicarbonate solution (500 mL) and brine (500 mL). Theorganic layer was dried over anhydrous sodium sulfate, and wasconcentrated under reduced pressure. The crude residue was purified viaSiO₂ column chromatography (220 g SiO₂ Combiflash HP Gold Column, 0-100%ethyl acetate/hexanes) to afford intermediate 1d.

LC/MS: t_(R)=1.50 min, MS m/z=553.34 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6 mm

Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid; Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.2 min 100% ACN, 2.2min-2.4 min 100%-2% ACN, 2.4 min-2.5 min 2% ACN.

HPLC: t_(r)=3.442 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

TLC: eluent: ethyl acetate, R_(f)=0.5 (UV)

Intermediate1e—7-((2S,3S,4R,5R)-3,4-bis(benzyloxy)-5-(benzyloxymethyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-amine

To a solution of intermediate 1d (4.74 g, 8.58 mmol) and triethylsilane(3.56 mL, 22.3 mmol), in DCM (43 mL) was added boron trifluoride diethyletherate (1.59 ml, 12.9 mmol) slowly via syringe at 0° C. under an argonatmosphere. After 2 h, the reaction mixture was slowly diluted withsaturated aqueous sodium bicarbonate solution (100 mL), and theresulting mixture was extracted with ethyl acetate (2×150 mL), was driedover anhydrous sodium sulfate, and was concentrated under reducedpressure. The crude residue was purified via SiO₂ column chromatography(24 g SiO₂ Combiflash HP Gold Column, 0-100% ethyl acetate/hexanes) toafford intermediate 1e.

¹H NMR (400 MHz, CDCl₃) δ 7.88 (s, 1H), 7.37-7.22 (m, 15H), 6.73 (d,J=4.6 Hz, 1H), 6.71 (d, J=4.6 Hz, 1H), 5.66 (d, J=4.2 Hz, 1H), 4.71 (s,2H), 4.60 (d, J=12.0 Hz, 1H), 4.54 (s, 2H), 4.45 (d, J=11.9 Hz, 1H),4.39 (dt, J=7.1, 3.6 Hz, 1H), 4.25 (t, J=4.6 Hz, 1H), 4.14-4.10 (m, 1H),3.78 (dd, J=10.7, 3.4 Hz, 1H), 3.65 (dd, J=10.7, 4.0 Hz, 1H).

LC/MS: t_(R)=2.01 min, MS m/z=537.41 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6mm; Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid; Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.2 min 100% ACN, 2.2min-2.4 min 100%-2% ACN, 2.4 min-2.5 min 2% ACN at 2 μl/min.

HPLC: t_(R)=3.596 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

TLC: eluent: ethyl acetate, R_(f)=0.3 (UV)

Intermediate1f—N-(7-((2S,3S,4R,5R)-3,4-bis(benzyloxy)-5-(benzyloxymethyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

To a solution of intermediate 1e (3.94 g, 7.34 mmol) in pyridine (36.7mL) was added benzoyl chloride (1.69 ml, 14.68 mmol) slowly at RT underan argon atmosphere. After 1 h, additional benzoyl chloride (1.69 ml,14.68 mmol) was added slowly. After 19 h, water (20 mL) was added slowlyand the reaction mixture became slightly cloudy. Ammonium Hydroxide (˜10mL) was then added slowly until the reaction mixture was basic at pH=10.After 1 h, water (150 mL) was added dropwise via addition funnel andwhite solids slowly began to precipitate from the reaction mixture overthe course of the addition. The resulting mixture was stirred for 24 hand the white solids were collected by vacuum filtration and were driedazeotropically from toluene to afford intermediate 1f.

¹H NMR (400 MHz, CDCl₃) δ 8.23 (br s, 1H), 7.62 (t, J=7.8 Hz, 1H), 7.53(t, J=7.6 Hz, 2H), 7.38-7.21 (m, 18H), 7.17 (d, J=7.6 Hz, 1H), 5.69 (d,J=4.1 Hz, 1H), 4.71 (s, 2H), 4.63-4.44 (m, 4H), 4.43-4.39 (m, 1H), 4.22(t, J=4.5 Hz, 1H), 4.15-4.10 (m, 1H), 3.79 (dd, J=10.8, 3.2 Hz, 1H),3.65 (dd, J=10.7, 3.7 Hz, 1H).

LC/MS: t_(R)=1.91 min, MS m/z=641.18 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6mm; Solvents:

Acetonitrile with 0.1% acetic acid, Water with 0.1% acetic acid;Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.2 min 100% ACN, 2.2min-2.4 min 100%-2% ACN, 2.4 min-2.5 min 2% ACN at 2 μl/min.

TLC: eluent: 50% ethyl acetate in hexanes, R_(f)=0.6 (UV)

Intermediate1g—N-(7-((2S,3R,4S,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

Ethanol (68.5 mL) and formic acid (51.7 mL, 1.37 mol) were addedsequentially to a mixture of intermediate 1f (4.39 g, 6.85 mmol) andpalladium on carbon (10% by wt, 2.2 g) at RT under an argon atmosphere.After 3 d, the reaction mixture was filtered through a pad of celite,and the filtrate was concentrated under reduced pressure. The cruderesidue was azeotroped with toluene (3×20 mL) to afford intermediate 1g,which was used directly in the next step without further purification.

¹H NMR (400 MHz, CD₃OD) δ 8.15 (s, 1H), 7.67-7.40 (m, 5H), 7.23 (d,J=4.7 Hz, 1H), 7.00 (d, J=4.7 Hz, 1H), 5.40 (d, J=6.0 Hz, 1H), 4.44 (t,J=5.7 Hz, 1H), 4.17 (t, J=5.1 Hz, 1H), 4.03 (q, J=4.3 Hz, 1H), 3.81 (dd,J=12.1, 3.5 Hz, 1H), 3.71 (dd, J=12.0, 4.5 Hz, 1H).

LC/MS: t_(R)=1.04 min, MS m/z=371.15 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6 mm

Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid; Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.2 min 100% ACN, 2.2min-2.4 min 100%-2% ACN, 2.4 min-2.5 min 2% ACN at 2 μl/min.;

HPLC: t_(R)=2.055 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

Intermediate 1h—N-(7-((2S,3R,4S,5R)-5-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-3,4-dihydroxytetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

4,4′-Dimethoxytrityl chloride (2.23 g, 6.59 mmol) was added as a solidin one portion to a solution of intermediate 1g (2.44 g, 6.59 mmol) inpyridine (32.5 mL) at RT. After 5.5 h, the reaction mixture was dilutedwith ethyl acetate (300 mL) and the resulting mixture was washed withbrine (3×200 mL). The organic layer was concentrated under reducedpressure, and the crude residue was purified via SiO₂ columnchromatography (80 g SiO₂ Combiflash HP Gold Column, 0-100% ethylacetate/hexanes) to afford intermediate 1h.

LC/MS: t_(R)=1.68 min, MS m/z=673.22 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6 m;

Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid; Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.2 min 100% ACN, 2.2min-2.4 min 100%-2% ACN, 2.4 min-2.5 min 2% ACN at 2 μl/min.

HPLC: t_(R)=4.270 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

TLC: eluent: 50% ethyl acetate in hexanes, R_(f)=0.15 (UV)

Intermediate1i—N-(7-((2S,3S,4R,5R)-5-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-3,4-bis(tert-butyldimethylsilyloxy)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

tert-Butyldimethylsilyl chloride (2.47 g, 16.4 mmol) was added to asolution of intermediate 1h (1.84 g, 2.74 mmol) and imidazole (2.23 g,32.8 mmol) in N,N-dimethylformamide (28.2 mL) at RT. After 17 h,saturated aqueous sodium bicarbonate solution (500 mL) was added slowlyto the reaction mixture. The resulting mixture was extracted with ethylacetate (500 mL), and the organic layer was washed with brine (2×400mL), was dried over anhydrous sodium sulfate, and was concentrated underreduced pressure. The crude residue was purified via SiO₂ columnchromatography (80 g SiO₂ Combiflash HP Gold Column, 0-100% ethylacetate/hexanes) to afford intermediate 1i.

LC/MS: t_(R)=3.43 min, MS m/z=901.37 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6 mm

Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.55 min 100% ACN,3.55 min-4.2 min 100%-2% ACN at 2 μl/min

HPLC: t_(R)=5.724 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

TLC: eluent: 50% ethyl acetate in hexanes, R_(f)=0.75 (UV)

Intermediate1j—N-(7-((2S,3S,4R,5R)-3,4-bis(tert-butyldimethylsilyloxy)-5-(hydroxymethyl)tetrahydrofuran-2-yl)pyrrolo[1,24][1,2,4]triazin-4-yl)benzamide

A solution of p-toluenesulfonic acid monohydrate (509 mg, 2.67 mmol) inmethanol (3.7 mL) was slowly added to a solution of intermediate 1i(2.41 g, 2.67 mmol) in dichloromethane (22.3 mL) at 0° C. After 1.5 h,the reaction mixture was diluted with saturated aqueous bicarbonatesolution (100 mL), and the resulting mixture was extracted withdichloromethane (2×100 mL). The combined organic extracts were driedover anhydrous sodium sulfate, and were concentrated under reducedpressure. The crude residue was purified via SiO₂ column chromatography(120 g SiO₂ Combiflash HP Gold Column, 0-100% ethyl acetate/hexanes) toafford intermediate 1j.

¹H NMR (400 MHz, CDCl₃) δ 8.72 (br-s, 1H), 8.16 (br-t, J=7.1 Hz, 2H),8.07 (br-t, J=7.7 Hz, 3H), 7.49-7.43 (m, 1H), 5.75 (d, J=8.2 Hz, 1H),5.28 (dd, J=8.1, 4.7 Hz, 1H), 4.81 (d, J=5.0 Hz, 1H), 4.70-4.63 (m, 1H),4.44 (d, J=12.3 Hz, 1H), 4.24 (d, J=12.4 Hz, 1H), 1.48 (s, 9H), 1.30 (s,9H), 0.65 (s, 3H), 0.64 (s, 3H), 0.41 (s, 3H), 0.00 (s, 3H).

LC/MS: t_(R)=2.66 min, MS m/z=599.19 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6 mm

Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05 min 100% ACN,3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2 μl/min.

HPLC: t_(R)=5.622 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

TLC: eluent: 50% ethyl acetate in hexanes, R_(f)=0.55 (UV)

Intermediate1k—N-(7-((2S,3S,4R,5S)-3,4-bis(tert-butyldimethylsilyloxy)-5-(iodomethyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

Intermediate 1j (1.19 g, 1.99 mmol) was added to a solution ofmethyltriphenoxyphosphonium iodide (0.99 g, 2.19 mmol) in DMF (9.9 mL)at RT. After 3 h, an additional portion of methyltriphenoxyphosphoniumiodide (0.99 g, 2.19 mmol) was added. After 1 h, the reaction mixturewas diluted with ethyl acetate (200 mL) and was washed with brine (3×100mL). The organic layer was dried over anhydrous sodium sulfate, and wasconcentrated under reduced pressure. The crude residue was purified viaSiO₂ column chromatography (80 g SiO₂ Combiflash HP Gold Column, 0-100%ethyl acetate/hexanes) to afford intermediate 1k.

¹H NMR (400 MHz, CDCl₃) δ 8.21 (br s, 1H), 7.61 (br t, J=7.2 Hz, 1H),7.53 (br t, J=7.5 Hz, 3H), 7.05 (br s, 1H), 5.44 (d, J=4.5 Hz, 1H), 4.52(t, J=4.3 Hz, 1H), 4.08-3.99 (m, 2H), 3.55 (dd, J=10.7, 5.2 Hz, 1H),3.38 (dd, J=10.7, 5.0 Hz, 1H), 0.93 (s, 9H), 0.85 (s, 9H), 0.16 (s, 3H),0.11 (s, 3H), −0.01 (s, 3H), −0.11 (s, 1H).

LC/MS: t_(R)=3.06 min, MS m/z=709.16 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6 mm

Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05 min 100% ACN,3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2 μl/min.

HPLC: t_(R)=5.837 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

TLC: eluent: 20% ethyl acetate in hexanes, R_(f)=0.45 (UV)

Intermediate1l—N-(7-((2S,3S,4S)-3,4-bis(tert-butyldimethylsilyloxy)-5-methylenetetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

Potassium t-butoxide (700 mg, 6.24 mmol) was added to a solution ofintermediate 1k (1.77 g, 2.5 mmol) in pyridine (25 mL) at RT. After 2 h,the reaction mixture was diluted with saturated aqueous sodiumbicarbonate solution (25 mL) and brine (200 mL). The resulting mixturewas extracted with ethyl acetate (300 mL). The organic layer was thenwashed with brine (200 mL), was dried over anhydrous sodium sulfate, andwas concentrated under reduced pressure. The crude residue was purifiedvia SiO₂ column chromatography (40 g SiO₂ Combiflash HP Gold Column,0-100% ethyl acetate/hexanes) to afford intermediate 1l.

LC/MS: t_(R)=2.87 min, MS m/z=581.37 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6 mm

Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid

Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05 min 100% ACN, 3.05min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2 μl/min.

HPLC: t_(R)=5.750 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

TLC: eluent: 50% ethyl acetate in hexanes, R_(f)=0.20 (UV)

Intermediate1m—N-(7-((2S,3S,4S)-3,4-bis(tert-butyldimethylsilyloxy)-5-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

DMDO (0.07M solution in acetone, 13.8 mL, 0.964 mmol) was added to asolution of intermediate 1l (560 mg, 0.964 mmol) in acetone (4.82 mL) at0° C. After 10 min, the reaction mixture was concentrated under reducedpressure was dried azeotropically with toluene (2×1 mL) to afford 1mthat was used immediately in the next step without further purification.

LC/MS: t_(R)=2.57 min, MS m/z=615.14 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6 mm

Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid

Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05 min 100% ACN, 3.05min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2 μl/min.

Intermediate1n—N-(7-((2S,3S,4S)-3,4-bis(tert-butyldimethylsilyloxy)-5-cyano-5-((trimethylsilyloxy)methyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

To a solution of crude intermediate 1m (—592 mg, ˜0.964 mmol) andtrimethylsilyl cyanide (640 μl, 4.80 mmol) in dichloromethane (19.2 mL)was added indium (III) bromide (681 mg, 1.92 mmol) at 0° C. under anargon atmosphere. After 4.5 h, the reaction mixture was quenched withsaturated aqueous sodium bicarbonate solution (6 mL) and was allowed towarm to RT. The resulting mixture was partitioned betweendichloromethane (20 mL) and saturated aqueous sodium bicarbonatesolution (20 mL). The phases were split and the aqueous layer wasextracted with dichloromethane (20 mL). The combined organic layers weredried over anhydrous sodium sulfate and were concentrated under reducedpressure to afford intermediate 1n (1:1 diastereomeric mixture) (710 mg)that was used directly in the next step without further purification.

LC/MS: first eluting isomer t_(r)=2.91 min, MS m/z=696.28 [M+1], secondeluting isomer t_(R)=3.02 min, MS m/z=696.19 [M+1],; LC system: ThermoAccela 1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6 mm

Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05 min 100% ACN,3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2 μl/min.

Intermediate1o—N-(7-((2S,3R,4S)-5-cyano-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

To a solution of crude intermediate 1n (668.23 mg, 0.96 mmol) in DMF(9.6 mL) was added cesium fluoride (729 mg, 4.8 mmol) at RT. After 5 h,the reaction mixture was diluted with brine (100 mL), and the resultingmixture was extracted with dichloromethane (3×100 mL). The combinedorganic layers were dried over anhydrous sodium sulfate and wereconcentrated under reduced pressure to afford intermediate 1o (1:1diastereomeric mixture) that was used directly in the next step withoutfurther purification.

LC/MS: first eluting isomer t_(R)=1.31 min, MS m/z=396.19 [M+1], secondeluting isomer t_(R)=1.32 min, MS m/z=396.19 [M+1],; LC system: ThermoAccela 1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6 mm

Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05 min 100% ACN,3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2 μl/min.

Example 1(2R,3S,4R,5S)-5-(4-aminopyrrolo[1,2-f][1,2,4]triazin-7-yl)-3,4-dihydroxy-2-(hydroxymethyl)tetrahydrofuran-2-carbonitrile

Methylamine (40% in water, 0.3 mL) was added to a solution of crudeintermediate 1o in methanol (1 mL) at RT. After 2.5 h, the reactionmixture was concentrated under reduced pressure, and was directlypurified by preparatory HPLC (Phenominex Luna 5u C18 100 Å 100×30 mmcolumn, 5-15% acetonitrile/water gradient, 25 min). The fractionscontaining the desired product and the 4′ anomer were combined and wereconcentrated under reduced pressure. The 4′ anomers were then separatedby preparatory HPLC (Phenominex Luna 5u C18 100 Å 100×30 mm column,5-15% acetonitrile/water gradient, 25 min). The fractions containing thedesired product were combined and were lyophilized to afford Example 1.

¹H NMR (400 MHz, CD₃OD) δ 7.79 (s, 1H), 6.85 (d, J=4.5 Hz, 1H), 6.76 (d,J=4.5 Hz, 1H), 5.45 (d, J=5.9 Hz, 1H), 4.59 (t, J=5.7 Hz, 1H), 4.40 (d,J=5.6 Hz, 1H), 3.88 (d, J=12.0 Hz, 1H), 3.80 (d, J=12.0 Hz, 1H).

LC/MS: t_(R)=0.29 min, MS m/z=292.16 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6 mm

Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid; Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.2 min 100% ACN, 2.2min-2.4 min 100%-2% ACN, 2.4 min-2.5 min 2% ACN at 2 μl/min.

HPLC: t_(R)=0.377 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.; HPLC: t_(R)=6.643 min; HPLC system: Agilent 1100 series.;Column: Luna 5μ C18(2) 110A, 250×4.6 mm; Solvents: Acetonitrile, Water;Gradient: 5-15% ACN over 10 min at 2 mL/min

Intermediate2b—N-(7-((2S,3R,4R,5R)-3-fluoro-4-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

To an N₂ purged flask was added intermediate 2a,(2R,3R,4R,5S)-5-(4-aminopyrrolo[1,2-f][1,2,4]triazin-7-yl)-4-fluoro-2-(hydroxymethyl)tetrahydrofuran-3-ol(prepared according to WO2012037038A1, 1.20 g, 4.01 mmol) (dried bycoevaporation with pyridine 3 times), which was then dissolved inpyridine (18 mL). Chlorotrimethylsilane (1.54 mL, 13.13 mmol) was addedin one portion at 0° C. and the resulting mixture was stirred under anN₂ atmosphere for 1 h. Benzoyl chloride (675 μL, 5.82 mmol) was addeddropwise and the reaction mixture was stirred for 1h. An additionalportion of benzoyl chloride (100 μL) was added to consume the remainingstarting material. A mixture of mono- and bis-Bz protected products wasobserved. The reaction was quenched with H₂O (5 mL), and the resultingmixture was stirred for 5 min. Then concentrated NH₄OH_((aq)) (8 mL) wasadded in one portion and allowed to stir for 15 min at which point thebis-Bz product was converted to the desired product. The solvents wereremoved under reduced pressure, and then the residue was coevaporatedwith CH₃OH. Intermediate 2b was isolated after purification by silicagel chromatography, using an eluent ramp of 50%-100% EtOAc in hexanes.

¹H NMR (400 MHz, DMSO-d₆) δ 8.26-7.91 (m, 2H), 7.88-7.79 (m, 1H), 7.61(t, J=7.5 Hz, 1H), 7.56-7.36 (m, 2H), 7.37-7.24 (m, 1H), 7.10 (d, J=4.6Hz, 1H), 7.01 (s, 1H), 5.53 (d, J=23.4 Hz, 1H), 5.45 (d, J=6.5 Hz, 1H),5.16-4.91 (m, 1H), 4.86 (t, J=5.6 Hz, 1H), 4.21-4.04 (m, 1H), 3.82 (dd,J=8.0, 3.9 Hz, 1H), 3.71 (ddd, J=12.3, 5.6, 2.6 Hz, 1H), 3.52 (ddd,J=12.2, 5.7, 4.5 Hz, 1H).

¹⁹F NMR (376 MHz, DMSO-d₆) δ −196.33 (dt, J=55.1, 22.5 Hz).

LC/MS: t_(R)=0.77 min, MS m/z=373.14 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80 min 100% ACN, 1.8min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN.

Intermediate2c—N-(7-((2S,3R,4R,5R)-5-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-3-fluoro-4-hydroxytetrahydrofuran-2-yl)pyrrolo[1,24][1,2,4]triazin-4-yl)benzamide

Intermediate 2b (1.3 g, 3.49 mmol) was dried by coevaporation withpyridine. The dried material was then dissolved in pyridine (15 mL)under an N₂ atmosphere. 4,4′-Dimethoxytrityl chloride (1.71 g, 5.0 mmol)was added in one portion at room temperature and allowed to stir for 2h. Ethanol (2 mL) was added and the resulting solution was stirred for 5min. Solvents were removed under reduced pressure. The residue waspurified by silica gel chromatography, using an eluent ramp of 0%-100%EtOAc in hexanes, to afford intermediate 2c.

¹H NMR (400 MHz, DMSO-d₆) δ 8.28-8.02 (m, 2H), 7.61 (t, J=7.5 Hz, 1H),7.51 (t, J=7.6 Hz, 2H), 7.36 (ddt, J=6.0, 4.7, 2.0 Hz, 2H), 7.31-7.04(m, 7H), 6.90-6.73 (m, 4H), 5.62 (d, J=24.4 Hz, 1H), 5.49 (d, J=7.0 Hz,1H), 5.27-5.01 (m, 1H), 4.32-4.13 (m, 1H), 4.06-3.95 (m, 1H), 3.69 (s,4H), 3.28 (s, 3H), 3.12 (dd, J=10.4, 5.2 Hz, 1H).

¹⁹F NMR (376 MHz, DMSO-d₆) δ −195.58 (dt, J=52.1, 24.7 Hz).

LC/MS: t_(R)=1.37 min, MS m/z=675.29 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80 min 100% ACN, 1.8min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN.

Intermediate2d—N-(7-((2S,3S,4R,5R)-4-(tert-butyldimethylsilyloxy)-3-fluoro-5-(hydroxymethyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

To a solution of intermediate 2c (1.47 g, 2.18 mmol) in DMF (8 mL),prepared under an N₂ atmosphere, was added imidazole (251 mg, 3.70mmol), followed by tert-butylchlorodimethylsilane (492 mg, 3.27 mmol).The solution was allowed to stir at room temperature for 16 h. Thesolution was diluted with H₂O (5 mL) and then the solvents were removedunder reduced pressure. The residue was partitioned between EtOAc andH₂O. The layers were separated and the organic phase was then washedwith brine. The organics were dried over Na₂SO₄, which was removed byfiltration, and the filtrate was concentrated under reduced pressure.The crude material was used as is in the next step.

The crude material was dissolved in CHCl₃ (15 mL) and cooled to 0° C.p-Toluenesulfonic acid hydrate (414 mg, 2.18 mmol) dissolved in CH₃OH (6mL) was added dropwise to the mixture and was allowed to stir for 15min. The reaction was quenched with sat. NaHCO_(3(aq)). The organicswere washed with brine and dried over Na₂SO₄, filtered and the solventwas removed under reduced pressure. The residue was purified by silicagel chromatography, using an eluent ramp of 0%-50% EtOAc in hexanes, toafford intermediate 2d.

¹H NMR (400 MHz, DMSO-d₆) δ 8.21-7.98 (m, 2H), 7.51 (dt, J=39.9, 7.5 Hz,3H), 7.12-6.86 (m, 2H), 5.48 (d, J=21.9 Hz, 1H), 5.07 (dt, J=54.6, 3.8Hz, 1H), 4.86 (t, J=5.5 Hz, 1H), 4.28 (ddd, J=17.8, 7.1, 4.4 Hz, 1H),3.83-3.72 (m, 1H), 3.63 (ddd, J=12.1, 5.2, 3.0 Hz, 1H), 3.43 (ddd,J=12.1, 6.0, 4.2 Hz, 1H), 0.80 (s, 9H), 0.01 (s, 3H), 0.00 (s, 3H).

¹⁹F NMR (376 MHz, DMSO-d₆) δ −198.05 (dt, J=54.2, 19.8 Hz).

LC/MS: t_(R)=1.35 min, MS m/z=487.24 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80 min 100% ACN, 1.8min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN.

Intermediate2e—N-(7-((2S,3S,4R)-4-(tert-butyldimethylsilyloxy)-3-fluoro-5,5-bis(hydroxymethyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

To solution of intermediate 2d (856 mg, 1.75 mmol) in toluene (4 mL),and DMSO (6 mL), prepared under an N₂ atmosphere, was added1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDCl) (504mg, 2.63 mmol). To this mixture was added pyridine (150 μL), and TFA (70μL) and the mixture was stirred at RT for 15 min. Additional EDOI (100mg) and pyridine (100 μL) was added and the mixture was stirred for anadditional 45 min. The reaction was quenched with H₂O (10 mL) and CH₂Cl₂(10 mL). The organics were washed with brine and dried over Na₂SO₄,filtered, and the solvent was removed under reduced pressure to affordthe crude aldehyde, which was used as is for the next step.

The crude aldehyde was dissolved in dioxane (5 mL) and 37%formaldehyde_((aq)) (925 μL) was added followed by 2N NaOH_((aq)) (925μL). After stirring at room temperature for 3 h, the reaction wasquenched with AcOH, diluted with EtOAc, and washed with H₂O. Theorganics were dried over Na₂SO₄, filtered, and the solvent was removedunder reduced pressure to afford the crude aldol product, which wascarried forward as is to the next step.

The crude aldol product was dissolved in EtOH (9 mL) under an N₂atmosphere and cooled to 0° C. NaBH₄ (80 mg, 2.1 mmol) was added in oneportion and the reaction was stirred for 10 min. The reaction wasquenched with AcOH, diluted with CH₂Cl₂ and washed with a 1:1 solutionof water and sat. NaHCO_(3(aq)). The organic phase was dried overNa₂SO₄, filtered, and the solvent was removed under reduced pressure.The residue was purified by silica gel chromatography, using an eluentramp from 0%-100% EtOAc in hexanes, to afford intermediate 2e.

¹H NMR (400 MHz, DMSO-d₆) δ 8.20-7.99 (m, 2H), 7.51 (dt, J=39.5, 7.5 Hz,3H), 7.15-6.93 (m, 2H), 5.50 (d, J=14.1 Hz, 1H), 5.24 (dt, J=54.2, 5.4Hz, 1H), 4.78 (t, J=5.6 Hz, 1H), 4.48 (dd, J=10.7, 4.8 Hz, 1H), 4.34(dd, J=6.7, 4.9 Hz, 1H), 3.62 (dd, J=11.9, 4.9 Hz, 1H), 3.55-3.35 (m,3H), 0.82 (s, 9H), 0.07 (s, 3H), −0.09 (s, 3H).

¹⁹F NMR (376 MHz, DMSO-d₆) δ −200.37 (d, J=51.1 Hz).

LC/MS: t_(R)=1.25 min, MS m/z=517.21 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80 min 100% ACN, 1.8min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN.

Intermediate2f—N-(7-((2S,3S,4R,5R)-5-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-4-(tert-butyldimethylsilyloxy)-5-((tert-butyldimethylsilyloxy)methyl)-3-fluorotetrahydrofuran-2-yl)pyrrolo[1,24][1,2,4]triazin-4-yl)benzamide

Intermediate 2e (370 mg, 0.717 mmol) was dissolved in CH₂Cl₂ (10 mL) andTEA (200 μL) under an N₂ atmosphere, and was then cooled to 0° C.4,4′-Dimethoxytrityl chloride 4,4′-Dimethoxytrityl chloride (0.364g,1.07 mmol) was added in one portion and the reaction mixture was allowedto stir for 30 min. CH₃OH (2 mL) was added and the solution was dilutedwith CH₂Cl₂ and sat. NaHCO_(3(aq)). The organic layer was washed withbrine, dried over Na₂SO₄, filtered, and the solvents were removed underreduced pressure. The residue was purified by silica gel chromatography,using an eluent ramp of 5%-100% EtOAc in hexanes, to afford the crudeproduct as a mixture of bis-DMTr and 4′β products. This mixture wascarried forward without further purification.

To the crude product (574 mg, mixture) in DMF (3 mL), under an N₂atmosphere, was added imidazole (143 mg, 2.10 mmol), followed bytert-butylchlorodimethylsilane (158 mg, 1.05 mmol). The solution wasallowed to stir at room temperature for 2 h. The solution was dilutedwith CH₃OH (1 mL) and EtOAc. The organics were washed with H₂O and thenwith brine. The organic layer was dried over Na₂SO₄, filtered, and thesolvent was removed under reduced pressure. The residue was purified bysilica gel chromatography, using an eluent ramp of 0%-50% EtOAc inhexanes, to afford intermediate 2f that contained some bis-DMTrmaterial.

LC/MS: t_(R)=2.25 min, MS m/z=933.52 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.8 min 100% ACN, 2.8min-2.85 min 100%-2% ACN, 2.85 min-3 min 2% ACN.

Intermediate2g—N-(7-((2S,3S,4R,5R)-4-(tert-butyldimethylsilyloxy)-5-((tert-butyldimethylsilyloxy)methyl)-3-fluoro-5-(hydroxymethyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

Intermediate 2f was dissolved in CHCl₃ (5 mL) and was cooled to 0° C.p-Toluenesulfonic acid hydrate (90 mg, 0.474 mmol), dissolved in CH₃OH(4 mL) was added dropwise to the mixture and the reaction mixture wasallowed to stir for 5 min. The reaction mixture was quenched with sat.NaHCO_(3(aq)). The organics were washed with brine, dried over Na₂SO₄,filtered, and the solvent was removed under reduced pressure. Theresidue was purified by silica gel chromatography, using an eluent rampof 0%-40% EtOAc in hexanes, to afford intermediate 2g.

¹H NMR (400 MHz, CDCl₃) δ 8.09-7.88 (m, 2H), 7.48 (dt, J=35.4, 7.4 Hz,3H), 7.30 (d, J=4.6 Hz, 1H), 6.88 (s, 1H), 5.69 (dd, J=18.8, 4.2 Hz,1H), 5.05 (dt, J=54.6, 4.7 Hz, 1H), 4.62 (dd, J=14.9, 5.1 Hz, 1H),3.91-3.64 (m, 3H), 0.92-0.70 (m, 18H), 0.13-0.04 (m, 6H), 0.01 (m, 6H).

¹⁹F NMR (376 MHz, CDCl₃) δ −196 (m)

LC/MS: t_(R)=2.61 min, MS m/z=631.43 [M+1]; C system: Thermo Accela 1250UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.8 min 100% ACN, 2.8min-2.85 min 100%-2% ACN, 2.85 min-3 min 2% ACN.

Intermediate2h—N-(7-((2S,3S,4R,5R)-5-((E)-2-bromovinyl)-4-(tert-butyldimethylsilyloxy)-5-((tert-butyldimethylsilyloxy)methyl)-3-fluorotetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

To solution of intermediate 2g (228 mg, 0.361 mmol) in toluene (0.75mL), and DMSO (0.15 mL), was added1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCl) (208mg, 1.08 mmol) under an N₂ atmosphere. To this mixture was addedpyridine (30 μL), and TFA (15 μL) and the mixture was stirred at RT for30 min. The reaction was diluted with EtOAc and washed with H₂O followedby brine. The organics were dried over Na₂SO₄, filtered, and solvent wasremoved under reduced pressure to afford the crude aldehyde. Thismaterial was used as is for the next step.

To a suspension of bromomethyltriphenylphosphonium bromide (314 mg, 0.72mmol) in THF (4 mL) at −40° C. was added KOtBu (1.0M in THF, 1.08 mL,1.08 mmol) and the reaction mixture was stirred for 2 h under an N₂atmosphere. The crude aldehyde was dissolved in THF (4 mL) and addeddropwise. The reaction mixture was removed from the cold bath andallowed to warm to 10° C. over 1 h. The reaction mixture was re-cooledto −40° C. and the reaction mixture was quenched with sat NH₄Cl_((aq)).The layers were separated and the organics were dried over Na₂SO₄,filtered, and solvent was removed under reduced pressure. The residuewas purified by silica gel chromatography, using an eluent of 0%-50%EtOAc in hexanes, to afford intermediate 2h.

¹H NMR (400 MHz, CDCl₃) δ 8.08-7.85 (m, 2H), 7.62-7.36 (m, 2H),7.34-7.01 (m, 3H), 6.92 (s, 1H), 6.60-6.45 (m, 1H), 6.35 (d, J=8.2 Hz,1H), 5.61 (d, J=25.1 Hz, 1H), 4.82 (dd, J=56.3, 4.9 Hz, 1H), 4.69-4.46(m, 1H), 3.97 (d, J=11.4 Hz, 1H), 3.53 (d, J=11.4 Hz, 1H), 0.84 (d,J=3.9 Hz, 18H), 0.13-−0.10 (m, 12H).

¹⁹F NMR (376 MHz, CDCl₃) δ −190.60 (m).

LC/MS: t_(R)=2.10 min, MS m/z=705.54/707.29 [M+1]; LC system: ThermoAccela 1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.8 min 100% ACN, 2.8min-2.85 min 100%-2% ACN, 2.85 min-3 min 2% ACN.

Intermediate2i—N-(7-((2S,3S,4R,5R)-4-(tert-butyldimethylsilyloxy)-5-((tert-butyldimethylsilyloxy)methyl)-5-ethynyl-3-fluorotetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

Intermediate 2h (204 mg, 0.289 mmol) was dissolved in THF (8 mL) underan N₂ atmosphere and cooled to −40° C. KOtBu (1.0M in THF, 1.08 mL, 1.08mmol) was slowly added. The reaction was allowed to stir for 20 min aswas quenched with sat. NH₄Cl_((aq)). The solution was diluted with EtOAcand washed with brine. The organics were dried over Na₂SO₄, filtered,and solvent was removed under reduced pressure. The residue was purifiedby silica gel chromatography, using an eluent ramp of 0%-50% EtOAc inhexanes, to afford intermediate 2i.

¹H NMR (400 MHz, CDCl₃) δ 8.12-7.88 (m, 2H), 7.51 (dt, J=36.5, 7.5 Hz,2H), 7.32 (d, J=4.6 Hz, 1H), 6.88 (s, 1H), 5.79 (d, J=22.1 Hz, 1H), 5.02(ddd, J=55.3, 5.1, 3.2 Hz, 1H), 4.56 (dd, J=18.1, 5.1 Hz, 1H), 3.91 (d,J=11.3 Hz, 1H), 3.83-3.62 (m, 1H), 2.55 (m, 1H), 0.90 (dd, J=25.3, 1.6Hz, 18H), 0.20-−0.08 (m, 12H).

¹⁹F NMR (376 MHz, CDCl₃) δ −193.10 (broad-s).

LC/MS: t_(R)=1.88 min, MS m/z=625.24 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.8 min 100% ACN, 2.8min-2.85 min 100%-2% ACN, 2.85 min-3 min 2% ACN.

Intermediate2j—N-(7-((2S,3R,4R,5R)-5-ethynyl-3-fluoro-4-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

To a solution of intermediate 2i (152 mg, 0.243 mmol) in THF (3.5 mL)under an N₂ atmosphere was added TBAF (1.0M in THF, 700 μL, 0.700 mmol)at room temperature and the mixture was allowed to stir for 30 min.Solvents were removed under reduced pressure. The residue was purifiedby silica gel chromatography, using an eluent ramp of 40%-100% EtOAc inhexanes, to afford intermediate 2j.

LC/MS: t_(R)=0.88 min, MS m/z=397.16 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.8 min 100% ACN, 2.8min-2.85 min 100%-2% ACN, 2.85 min-3 min 2% ACN.

Example 2(2R,3R,4R,5S)-5-(4-aminopyrrolo[1,2-f][1,2,4]triazin-7-yl)-2-ethynyl-4-fluoro-2-(hydroxymethyl)tetrahydrofuran-3-ol

To a solution of intermediate 2j (71 mg, 0.179 mmol) in CH₃OH (2 mL) wasadded con. NH₄OH_((aq)) (0.7 mL) and the resulting solution was stirredat room temperature for 16 h. Solvents were removed under reducedpressure. The residue was purified by silica gel chromatography, usingan eluent ramp of 0%-20% CH₃OH in CH₂Cl₂, followed by reverse phaseHPLC, using an eluent ramp of 0%-20% ACN in H₂O, to yield example 2.

¹H NMR (400 MHz, CD₃OD) δ 7.77 (s, 1H), 6.90-6.70 (m, 2H), 5.62 (dd,J=25.5, 2.6 Hz, 1H), 5.18 (ddd, J=56.0, 5.4, 2.7 Hz, 1H), 4.57 (dd,J=20.5, 5.4 Hz, 1H), 3.93-3.59 (m, 2H), 3.02 (d, J=0.7 Hz, 1H).

¹⁹F NMR (376 MHz, CD₃OD) δ −193.76 (ddd, J=56.0, 25.5, 20.4 Hz).

LC/MS: t_(R)=0.45 min, MS m/z=293.13 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80 min 100% ACN, 1.8min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN.

HPLC: t_(R)=3.112 min; HPLC system: Agilent 1100 series.

Column: Phenomenex Kinetex C18 2.6 μm 100A, 4.6×100 mm

Solvents: Acetonitrile with 0.1% TFA, Water with 0.1% TFA

Gradient: 0 min-8.0 min 2-98% ACN at 1.5 mL/min.

Intermediate3a—N-(7-((2S,3S,4R,5R)-4-(tert-butyldimethylsilyloxy)-5-((tert-butyldimethylsilyloxy)methyl)-3-fluoro-5-formyltetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

To a solution of intermediate 2g (1.13 g, 1.79 mmol) in DMSO (1 mL) andtoluene (10 mL), prepared under an N₂ atmosphere, was added EDCl.HCl(1.02 g, 5.36 mmol) and pyridine (149 μL, 1.92 mmol). TFA (74 μL, 0.97mmol) was added drop-wise. After 1 hr the reaction was checked by LC/MS.A single peak was observed, with a retention time similar to thestarting material's, but with an M+1 peak equal to that expected for theproduct. Another 50 μL of pyridine was added and the reaction wasstirred for another 15 min. No change by LC/MS. The reaction was dilutedwith EtOAc and quenched with a 1:1 mixture of sat. NaHCO_(3(aq.)) andH₂O. The mixture was partitioned between EtOAc and more H₂O. The organiclayer was separated and washed with H₂O, brine, and then dried overNa₂SO₄. The drying agent was removed by vacuum filtration and thefiltrate was concentrated. The residue was taken up in CH₂Cl₂,concentrated, and the resulting material was placed under high vacuumfor 1 h. The product, intermediate 3a was used as is in the nextreaction.

LC/MS: t_(R)=1.90 min, MS m/z=629.46 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo La) Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.8 min 100% ACN, 2.8min-2.85 min 100%-2% ACN, 2.85 min-3 min 2% ACN.

Intermediate3b—N-(7-((2S,3S,4R,5R)-4-(tert-butyldimethylsilyloxy)-5-((tert-butyldimethylsilyloxy)methyl)-3-fluoro-5-((E)-(hydroxyimino)methyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

To a solution of intermediate 3a (crude material from previous step,assumed 1.79 mmol) in pyridine (11 mL), prepared under an N₂ atmosphere,was added HONH₂.HCl in one portion at room temperature. The reaction waschecked by LC/MS 5 minutes later; starting material was consumed. Thereaction was checked again 25 minutes later. There was no change fromthe first time point. The reaction was concentrated and the residue waspartitioned between EtOAc and H₂O. The organic layer was separated,washed with brine, dried over Na₂SO₄ and filtered. The filtrate wasconcentrated, taken up in CH₂Cl₂, concentrated again, and the residuewas placed under high vacuum. The product intermediate 3b was used as isin the next reaction.

LC/MS: t_(R)=1.83 min, MS m/z=644.55 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.8 min 100% ACN, 2.8min-2.85 min 100%-2% ACN, 2.85 min-3 min 2% ACN.

Intermediate3c—N-(7-((2S,3S,4R,5R)-4-(tert-butyldimethylsilyloxy)-5-((tert-butyldimethylsilyloxy)methyl)-5-cyano-3-fluorotetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

To a solution of intermediate 3b (crude material from the previous step,assumed 1.79 mmol) in ACN (16 mL) was added CDI (436 mg, 2.69 mmol) in asingle portion. The reaction was run under an N₂ atmosphere. Thereaction was checked by LC/MS after 20 minutes. Peaks with the mass ofstarting material and product are barely time resolved. The reaction waschecked 1.5 h later. The UV peak corresponding to the starting materialwas nearly gone and the intensity of the mass peak was diminished. Thereaction was diluted with CH₂Cl₂ and quenched with a 1:1 mixture of sat.NaHCO_(3(aq.)) and H₂O. The layers were separated, the aqueous was backextracted with CH₂Cl₂ and the combined organics layers were extractedwith a 1:1 mixture of brine and H₂O, dried over Na₂SO₄ and filtered. Thefiltrate was concentrated and intermediate 3c was isolated by silica gelcolumn chromatography using the following solvent ramp: 0% EtOAc inhexanes ramping to 20% EtOAc in hexanes, pause at 20% EtOAc in hexanesand then ramping to 40% EtOAc in hexanes.

¹H NMR (400 MHz, DMSO-d₆) δ 8.31 (s, 1H), 8.07 (s, 1H), 7.65 (t, J=8 Hz,1H), 7.54 (t, J=8 Hz, 1H), 7.15 (d, 4 Hz, 1H), 7.02 (s, 1H), 5.82 (d,J=24 Hz, 1H), 5.51 (ddd, J=52, 4.8, 2.8 Hz, 1H), 4.70 (dd, J=18.4, 4.4Hz, 1H), 3.94 (dd, J=53.2, 11.2 Hz, 2H), 0.93 (s, 9H,), 0.84 (s, 9H),0.17 (s, 3H), 0.16 (s, 3H), 0.05 (s, 3H), 0.01 (s, 3H).

¹⁹F NMR (376 MHz, DMSO-d₆) δ −194.658 (dt, J=53, 21.4 Hz).

LC/MS: t_(R)=1.84 min, MS m/z=626.60 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.8 min 100% ACN, 2.8min-2.85 min 100%-2% ACN, 2.85 min-3 min 2% ACN.

Intermediate3d—(2R,3R,4S,5S)-5-(4-aminopyrrolo[1,24][1,2,4]triazin-7-yl)-3-(tert-butyldimethylsilyloxy)-2-((tert-butyldimethylsilyloxy)methyl)-4-fluorotetrahydrofuran-2-carbonitrile

To a solution of intermediate 3c (770 mg, 1.23 mmol) in MeOH (11.2 mL),cooled in an ice water bath, was added concentrated NH₄OH_((aq)) (3.74mL). The cold bath was removed and the resulting heterogeneous solutionwas stirred overnight. The next day the reaction was incomplete asdetermined by LC/MS. Additional concentrated NH₄OH_((aq)) (4 mL) and2-MeTHF (12 mL) was added. The reaction became homogenous but after 20minutes there was no additional reaction progress. The reaction wasconcentrated and the residue was dissolved in THF (15 mL). To thismixture was added concentrated NH₄OH_((aq)) (5 mL) and enough MeOH (1.9mL) to turn the solution homogenous and monophasic. The reaction wasstirred at room temperature for 22 h. The reaction was nearly complete(about 5% of the starting material remains). The reaction was dilutedwith CH₂Cl₂ and H₂O. The layers were separated, and the aqueous layerwas diluted with saturated NaHCO_(3(aq)) and extracted with CH₂Cl₂. Theaqueous layer was neutralized with 2N HCl and then extracted withCH₂Cl₂. The combined organic layers were dried over Na₂SO₄, which wasremoved by filtration. The filtrate was concentrated and intermediate 3dwas isolated from the residue by silica gel column chromatography usingthe following solvent ramp: 0% EtOAc in hexanes ramping to 50% EtOAc inhexanes, pause at 50% EtOAc in hexanes and then ramping to 100% EtOAc inhexanes.

LC/MS: t_(R)=1.59 min, MS m/z=522.47 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.8 min 100% ACN, 1.8min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN.

Example 3(2R,3R,4R,5S)-5-(4-aminopyrrolo[1,24][1,2,4]triazin-7-yl)-4-fluoro-3-hydroxy-2-(hydroxymethyl)tetrahydrofuran-2-carbonitrile

To a solution of intermediate 3d (100 mg, 0.191 mmol) in THF (2 mL), ina polypropylene tube, was added 70% HF.Pyridine in pyridine (60 μL,0.478 mmol) at 0° C., under an N₂ atmosphere. The reaction was checkedafter 20 minutes; there was no reaction, so additional 70% HF.Pyridinein pyridine (150 μL) was added and the cold bath was removed. After 1hour and 50 minutes additional 70% HF.Pyridine in pyridine (150 μL) wasadded. After another 2 hours additional 70% HF.Pyridine in pyridine (300μL) was added. After another 2 hours and 15 minutes additional 70%HF.Pyridine in pyridine (1 mL) was added. The reaction turns clear andhomogenous upon this final addition of 70% HF.Pyridine in pyridine. Thereaction was stirred overnight. The reaction was complete the next day.The reaction was cooled in an ice bath and quenched with H₂O and a smallamount of saturated NaHCO_(3(aq)). The mixture was concentrated and theresidue was taken up in DMSO. Remaining insoluble material was removedby filtration and the filtrate was semipurified by HPLC. The isolatedmaterial was dissolved in DMF and purified by HPLC. Example 3 wasisolated, with 0.5% as a TFA salt.

¹H NMR (400 MHz, DMF-d₇) δ 7.92 (s, 1H), 6.99 (d, J=4.4 Hz, 1H), 6.89(d, J=4.9 Hz, 1H), 6.64 (d, J=6 Hz, 1H), 5.92 (t, J=6.4 Hz, 1H), 5.83(dd, J=25.2, 2 Hz, 1H), 5.40 (ddd, J=54.8, 4.8, 2.4 Hz, 1H), 4.75 (dt,J=22, 5.2 Hz, 1H), 4.02 (dd, J=12, 6.4 Hz, 1H), 3.87 (dd, J=12, 6.4 Hz,1H).

¹⁹F NMR (376 MHz, DMF-d₇) δ −74.92 (s), −193.726 (dt, J=54.5, 23.3 Hz).

LC/MS: t_(R)=0.56 min, MS m/z=294.10 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.8 min 100% ACN, 1.8min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN.

HPLC: t_(R)=3.220 min; HPLC system: Agilent 1100 series.; Column:Phenomenex Kinetex C18 2.6 μm 100A, 4.6×100 mm; Solvents: Acetonitrilewith 0.1% TFA, Water with 0.1% TFA

Gradient: 0 min-8.0 min 2-98% ACN at 1.5 mL/min.

Intermediate4b—(3aR,5R,6aS)-5-((R)-2,2-dimethyl-1,3-dioxolan-4-yl)-2,2-dimethyldihydrofuro[3,2-d][1,3]dioxol-6(3aH)-one

Into a 10-L 4-necked round-bottom flask, was placed a solution ofintermediate 4a,(3aR,5S,6S,6aR)-5-((R)-2,2-dimethyl-1,3-dioxolan-4-yl-2,2-dimethyltetrahydrofuro[3,2-d][1,3]dioxol-6-ol(500 g, 1.90 mol) in dichloromethane/water (2.7 L/2.3 L) at roomtemperature. To this was added sodium carbonate (290 g, 3.42 mol).Addition of potassium carbonate (451 g, 3.24 mol) was next. This wasfollowed by the addition of 2,2,6,6-tetramethylpiperidinooxy (TEMPO,15.2 g, 96.31 mmol). To the mixture was added tetrabutylammonium bromide(31 g, 95.20 mmol). To the above was added N-bromosuccinimide (514 g,2.86 mol), in portions at 35° C. The resulting solution was allowed toreact, with stirring, for 2 h at room temperature. The resultingsolution was extracted with 2×1 L of dichloromethane and the organiclayers combined. The resulting mixture was washed with 1×1.5 L of water.The mixture was dried over anhydrous sodium sulfate and concentratedunder vacuum. This resulted in (crude) intermediate 4b.

Intermediate4c—(3aR,5S,6R,6aR)-5-((R)-2,2-dimethyl-1,3-dioxolan-4-yl)-2,2-dimethyltetrahydrofuro[3,2-d][1,3]dioxol-6-ol

Into a 2-L 4-necked round-bottom flask, was placed a solution ofintermediate 4b (370 g, 1.29 mol) in methanol (1300 mL). To the abovewas added sodium borohydride (26.4 g, 706.38 mmol), in portions at roomtemperature. The resulting solution was allowed to react, with stirring,for 2 h at room temperature. The resulting mixture was concentratedunder vacuum. The reaction was then quenched by the addition of 1000 mLof 5% aqueous ammonium chloride solution. The resulting solution wasextracted with 3×500 mL of dichloromethane and the organic layerscombined. The resulting solution was washed with 2×300 mL of water. Themixture was dried over anhydrous sodium sulfate and concentrated undervacuum. The crude product was purified by re-crystallization frompetroleum ether. This resulted in intermediate 4c.

Intermediate 4d

Into a 5000-mL 4-necked round-bottom flask, was placed a solution ofintermediate 4c (350 g, 1.34 mol) in dichloromethane (700 mL). To thiswas added tetrabutylammonium bromide (476.8 g, 1.48 mol). To the mixturewas added 50% sodium hydroxide/water (700 g). To the above was added2-(bromomethyl) naphthalene (340 g, 1.54 mol) in several batches. Theresulting solution was allowed to react, with stirring, for 4 h at roomtemperature. The reaction was then quenched by the addition of 1800 mLof dichloromethane/water (1:1). The resulting solution was extractedwith 2×1 L of dichloromethane and the organic layers combined. Theresulting mixture was washed with 1×1000 mL of water. The residue wasdissolved in 1000/1000 mL of petroleum ether/water. The crude productwas purified by re-crystallization from petroleum ether. This resultedin intermediate 4d.

Intermediate4e—(R)-1-((3aR,5R,6R,6aR)-2,2-dimethyl-6-(naphthalen-2-ylmethoxy)tetrahydrofuro[3,2-d][1,3]dioxol-5-yl)ethane-1,2-diol

Into a 5-L 4-necked round-bottom flask, was placed intermediate 4d (500g, 1.25 mol). To this was added acetic acid (1.8 L). To the mixture wasadded water (600 mL). The resulting solution was allowed to react, withstirring, overnight at room temperature. The solids were filtered out.The resulting solution was extracted with 3×1 L of petroleum ether andthe aqueous layers combined. The resulting solution was diluted with 2 Lof ethyl acetate. The resulting mixture was washed with 2×2 L of sodiumchloride_((aq)). The pH value of the solution was adjusted to 8 withsodium carbonate (50%). The resulting solution was extracted with 2×1 Lof ethyl acetate and the organic layers combined and concentrated undervacuum. This resulted in intermediate 4e.

Intermediate4f—(3aR,5S,6R,6aR)-2,2-dimethyl-6-(naphthalen-2-ylmethoxy)tetrahydrofuro[3,2-d][1,3]dioxole-5-carbaldehyde

Into a 10 L 4-necked roundbottom flask, was placed a solution ofintermediate 4e (300 g, 833.33 mmol) in 1,4-dioxane (2100 mL) at roomtemperature. This was followed by the addition of a solution of sodiumperiodate (250 g) in water (4000 mL) at room temperature in 0.5 h. Theresulting solution was allowed to react, with stirring, for 0.5 hr atroom temperature. The solids were filtered out. The resulting solutionwas extracted with 3×1000 mL of ethyl acetate and the organic layerscombined. The resulting mixture was washed with 2×1000 mL of sodiumchloride_((aq)). The resulting mixture was concentrated under vacuum.This resulted in intermediate 4f.

Intermediate4g—((3aR,6S,6aR)-2,2-dimethyl-6-(naphthalen-2-ylmethoxy)tetrahydrofuro[3,2-d][1,3]dioxole-5,5-diyl)dimethanol

Into a 10-L 4-necked round-bottom flask, was placed a solution ofintermediate 4f (250 g, 761.36 mmol) in water/tetrahydrofuran (1250/1250mL) at room temperature. To the above was added 2N sodiumhydroxide_((aq)) (1500 mL) dropwise with stirring at 0-15° C. To themixture was added formaldehyde (620 mL). The resulting solution wasallowed to react, with stirring, overnight at room temperature. Theresulting solution was extracted with 2×2000 mL of ethyl acetate. Theresulting mixture was washed with 2×2000 mL of sodium chloride_((aq)).The organic layers combined and dried over anhydrous sodium sulfate. Theresidue was applied onto a silica gel column with petroleum ether: ethylacetate (2/1). The crude product was re-crystallized from ethylacetate:ethanol in the ratio of 1g/(1 mL:1 mL). This resulted inintermediate 4g.

Intermediate4h—((3aR,5R,6S,6aR)-5-((tert-butyldiphenylsilyloxy)methyl)-2,2-dimethyl-6-(naphthalen-2-ylmethoxy)tetrahydrofuro[3,2-d][1,3]dioxol-5-yl)methanol

Into a 5-L 4-necked round-bottom flask purged and maintained with aninert atmosphere of nitrogen, was placed a solution of intermediate 4g(125 g, 346.84 mmol) in dichloromethane (2500 mL) at room temperature.To the mixture was added triethylamine (157.5 mL) at room temperature.To the above was added tert-butyldiphenylsilyl chloride (157.5 mL)dropwise with stirring at 0-10° C. The resulting solution was allowed toreact, with stirring, overnight at room temperature. The reaction wasthen quenched by the addition of 37.5 mL of methanol. The resultingmixture was washed with 2×500 mL of 5% hydrogen chloride_((aq)) and2×500 mL of sodium bicarbonate_((aq)). The resulting mixture was washedwith 2×500 mL of 1N sodium hydroxide_((aq)). The mixture was dried overanhydrous sodium sulfate and concentrated under vacuum. The crudeproduct was purified by re-crystallization from dichloromethane/hexane.This resulted in intermediate 4h.

Intermediate4i—tert-butyl(a3aR,5R,6S,6aR)-5-(iodomethyl)-2,2-dimethyl-6-(naphthalen-2-ylmethoxy)tetrahydrofuro[3,2-d][1,3]dioxol-5-yl)methoxy)diphenylsilane

Into a 1000-mL 3-necked round-bottom flask purged and maintained with aninert atmosphere of nitrogen, was placed a solution of intermediate 4h(20 g, 31.73 mmol) in toluene (320 mL), triphenylphosphine (35 g, 132.11mmol), imidazole (8.96 g, 132.26 mmol). This was followed by theaddition of iodine (16.95 g, 66.8 mmol) in several batches at 60° C. Theresulting solution was stirred overnight at 80° C. in an oil bath. Thereaction mixture was cooled to room temperature with a water/ice bath.The resulting solution was diluted with 1000 mL of ethyl acetate. Theresulting mixture was washed with 2×300 mL of sodium thiosulfate_((aq)).The resulting mixture was washed with 1×300 mL of sodiumchloride_((aq)). The mixture was dried over anhydrous sodium sulfate andconcentrated under vacuum. The residue was applied onto a silica gelcolumn with ethyl acetate/petroleum ether (1:10). This resulted inintermediate 4i.

Intermediate4j—tert-butyldiphenyl(((3aR,5R,6S,6aR)-2,2,5-trimethyl-6-(naphthalen-2-ylmethoxy)tetrahydrofuro[3,2-d][1,3]dioxol-5-yl)methoxy)silane

Into a 2000-mL round-bottom flask purged and maintained with an inertatmosphere of nitrogen, was placed a solution of intermediate 4i (66 g,88.47 mmol) in ethanol/ethyl acetate (600/600 mL), triethylamine (20.7g, 202.52 mmol), palladium on carbon (10% wt, 24.8 g, 23.30 mmol). Theresulting solution was stirred for 3 h at 40° C. The solids werefiltered out. The resulting mixture was concentrated under vacuum. Theresulting solution was diluted with 1500 mL of ethyl acetate. Theresulting mixture was washed with 1×500 mL of sodium chloride_((aq)).The mixture was dried over anhydrous sodium sulfate and concentratedunder vacuum. This resulted in intermediate 4j.

Intermediate4k—(3aR,5R,6S,6aR)-5-((tert-butyldiphenylsilyloxy)methyl)-2,2,5-trimethyltetrahydrofuro[3,2-d][1,3]dioxol-6-ol

Into a 500-mL round-bottom flask, was placed a solution of intermediate4j (1.0 g, 1.63 mmol) in dichloromethane (15 mL), water (1.25 mL), and2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ, 780 mg, 3.40 mmol). Theresulting solution was stirred for 1 h at room temperature. Theresulting solution was diluted with 50 mL of dichloromethane. Theresulting mixture was washed with 1×30 mL of water and 2×30 mL of sodiumbicarbonate_((aq)). The resulting mixture was washed with 1×30 mL ofsodium chloride_((aq)). The mixture was dried over anhydrous sodiumsulfate and concentrated under vacuum. The residue was applied onto asilica gel column with ethyl acetate/petroleum ether (1:20-1:10). Thisresulted in intermediate 4k.

Intermediate4l—(3aR,5R,6S,6aR)-5-(hydroxymethyl)-2,2,5-trimethyltetrahydrofuro[3,2-d][1,3]dioxol-6-ol

Into a 50-mL round-bottom flask, was placed a solution of intermediate4k (520 mg, 1.12 mmol) in tetrahydrofuran (9 mL), Tetrabutylammoniumfluoride (369 mg, 1.40 mmol). The resulting solution was stirred for 2 hat room temperature. The resulting mixture was concentrated undervacuum. The residue was applied onto a silica gel column withdichloromethane/methanol (100:1). This resulted in intermediate 4l.

¹H NMR (300 MHz, DMSO-d₆): δ 5.64 (d, J=3.9 Hz, 1H), 4.96 (d, J=6.6 Hz,1H), 4.67 (m, 1H), 4.55 (m, 1H), 4.05 (m, 1H), 3.24-3.30 (m, 1H),3.11-3.18 (m, 1H), 1.50 (s, 3H), 1.27 (s, 3H), 1.16 (s, 1H).

Intermediate4m—(3aR,5R,6S,6aR)-6-(benzyloxy)-5-(benzyloxymethyl)-2,2,5-trimethyltetrahydrofuro[3,2-d][1,3]dioxole

Into a 50-mL 3-necked round-bottom flask purged and maintained with aninert atmosphere of nitrogen, was placed a solution of intermediate 4l(180 mg, 0.84 mmol) in tetrahydrofuran (4 mL). This was followed by theaddition of sodium hydride (60% wt., 140 mg, 3.50 mmol), in portions at0° C. The resulting solution was stirred for 30 min at 0° C. Theresulting solution was allowed to react, with stirring, for anadditional 30 min at room temperature. To this was added benzyl bromide(452 mg, 2.62 mmol) dropwise with stirring at 0° C. The resultingsolution was allowed to react, with stirring, for an additional 3 h atroom temperature. The reaction was then quenched by the addition of 30mL of ammonium chloride_((aq)). The resulting solution was extractedwith 50 mL of dichloromethane and the organic layers were combined anddried over anhydrous sodium sulfate and concentrated under vacuum. Theresidue was applied onto a silica gel column with ethylacetate/petroleum ether (1:30-1:20). This resulted in intermediate 4m.

Intermediate4n—(2R,3R,4S,5R)-4-(benzyloxy)-5-(benzyloxymethyl)-5-methyltetrahydrofuran-2,3-diyldiacetate

Into a 1000-mL round-bottom flask, was placed intermediate 4m (Alsoprepared according to Biosci. Biotech. Biochem. 1993, 57, 1433-1438, 45g, 111.19 mmol), acetic acid (270 mL), acetic anhydride (90 mL),sulfuric acid (45 d). The resulting solution was stirred for 30 min atroom temperature. The reaction was then quenched by the addition of 1000mL of water/ice. The resulting solution was diluted with 3000 mL ofethyl acetate. The resulting mixture was washed with 2×1000 mL of waterand 4×1000 mL of sodium bicarbonate_((aq)). The resulting mixture waswashed with 2×1000 mL of sodium chloride_((aq)). The mixture was driedover anhydrous sodium sulfate and concentrated under vacuum. The residuewas applied onto a silica gel column with ethyl acetate/petroleum ether(1:30-1:20). This resulted in intermediate 4n.

¹H NMR (300 MHz, CDCl₃): δ 7.28-7.38 (m, 10H), 6.13 (s, 1H), 5.37 (d,J=4.8 Hz, 1H), 4.44-4.68 (m, 4H), 4.33 (d, J=5.1 Hz, 1H), 3.33-3.45 (m,2H), 2.15 (s, 3H), 1.88 (s, 3H), 1.35 (s, 3H).

MS m/z=451 [M+Na]

Intermediate4o—(3R,4S,5R)-4-(benzyloxy)-5-(benzyloxymethyl)-3-hydroxy-5-methyldihydrofuran-2(3H)-one

Intermediate 4n (1.3 g, 3 mmol) was dissolved in anhydrous MeOH (15 mL).Potassium carbonate powder (456 mg, 3.3 mmol) was added, and thereaction mixture was stirred for 1 h. The reaction mixture was thenconcentrated under reduced pressure. Added acetonitrile and stirred for5 minutes. Filtered off insoluble and washed with acetonitrile.Concentrated filtrate under reduced pressure. Dissolved resultingmaterial in anhydrous DCM (20 mL). Added tetrabutylammonium iodine (1.66g, 4.5 mmol) and N-iodo-succinimide (NIS, 1.69 g, 2.5 mmol). Stirred thereaction mixture in the dark for 16 h. Added more NIS (0.85 g, 1.25mmol) and stirred for 4 hours. Added more NIS (0.85 g, 1.25 mmol) andstirred for 2 days in the dark. Diluted reaction with EtOAc and washedwith aqueous sodium thiosulfate solution twice and then with saturatedaqueous sodium chloride solution. Dried organic portion over anhydroussodium sulfate and concentrated under reduced pressure. Purified withsilica gel column (0-30% EtOAc in hexanes) to afford intermediate 4o.

¹H NMR (400 MHz, CDCl₃): δ 7.35-7.22 (m, 10H), 4.82 (bs, 1H), 4.75-4.66(m, 2H), 4.55-4.44 (m, 2H), 4.13 (d, J=8 Hz, 1H), 3.70-3.45 (m, 2H),1.38 (s, 3H).

LC/MS: t_(R)=2.58 min, MS m/z=342.9 [M+1], 360.0 [M+H₂O]; LC/MS system:Thermo LCQ Advantage; Phenomenex Gemini, C₁₈, 5u, 110A, 30×4.6 mm;Buffer A: 0.1% Acetic acid in Water; Buffer B: 0.1% Acetic acid inAcetonitrile 5-100% Buffer B in 2.5 mins then 100% for 0.9 min @ 2mL/min.

HPLC: t_(R)=3.78 min; HPLC system: Agilent 1100; Phenomenex Gemini, C₁₈,5u, 110A, 50×4.6 mm; Buffer A: 0.05% TFA in Water; Buffer B: 0.05% TFAin Acetonitrile; 2-98% Buffer B in 5 minutes @ 2 mL/min.

Intermediate4p—(3R,4S,5R)-3,4-bis(benzyloxy)-5-(benzyloxymethyl)-5-methyldihydrofuran-2(3H)-one

Dissolved intermediate 4o (955 mg, 2.79 mmol) in EtOAc (10 mL). Addedbenzyl bromide (400 μL, 3.35 mmol) and silver(I) oxide (712 mg, 3.07mmol). Stirred at 60° C. under N₂(g) in the dark for 3 h. Added morebenzyl bromide (400 μL, 3.35 mmol) and stirred at 60° C. under N₂(g) inthe dark for 16 h. Added more silver(I) oxide (350 mg, 1.5 mmol) andstirred at 60° C. under N₂(g) in the dark for 8 h. Cooled to roomtemperature. Filtered off solids and washed with EtOAc. Concentratedfiltrate under reduced pressure to give an oil. Added hexanes andstirred for 2 h to give solid. Collected solid and washed with hexanes.Dried solid under high vacuum to afford intermediate 4p.

¹H NMR (400 MHz, CDCl₃): δ 7.35-7.16 (m, 15H), 5.03 (d, J=12 Hz, 1H),4.79-4.71 (m, 2H), 4.52-4.40 (m, 4H), 4.06 (d, J=6 Hz, 1H), 3.49-3.39(m, 2H), 1.38 (s, 3H).

LC/MS: t_(R)=2.91 min, MS m/z=433.1 [M+1], 450.1 [M+H₂O]; LC/MS system:Thermo LCQ Advantage; Phenomenex Gemini, C₁₈, 5u, 110A, 30×4.6 mm;Buffer A: 0.1% Acetic acid in Water; Buffer B: 0.1% Acetic acid inAcetonitrile; 5-100% Buffer B in 2.5 mins then 100% for 0.9 min @ 2mL/min.

HPLC: t_(R)=4.54 min; HPLC system: Agilent 1100; Phenomenex Gemini, C₁₈,5u, 110A, 50×4.6 mm; Buffer A: 0.05% TFA in Water; Buffer B: 0.05% TFAin Acetonitrile

2-98% Buffer B in 5 minutes @ 2 mL/min.

Intermediate4q—(3R,4S,5R)-2-(4-aminopyrrolo[1,2-f][1,2,4]triazin-7-yl)-3,4-bis(benzyloxy)-5-(benzyloxymethyl)-5-methyltetrahydrofuran-2-ol

Intermediate 1b (148 mg, 0.570 mmol) and1,2-bis(chlorodimethylsilyl)ethane (123 mg, 0.570 mmol) were dissolvedin anhydrous THF (20 mL) and stirred under Ar(g) at −70° C. Addedn-butyllithium (2.5M solution in hexanes, 684 μL, 1.71 mmol) dropwise tothe reaction mixture while maintaining internal temperature below −65°C. Allowed the reaction to warm to −40° C. and kept for 15 min. Asolution of intermediate 4p (224 mg, 0.518 mmol) in THF (10 mL)precooled to −70° C. was then added to the reaction mixture under Ar(g).The resulting solution was stirred for 2 h at −40° C. The reactionmixture was then poured into a stirring mixture of EtOAc and citricacid_((aq)). Stirred for 5 min. Collected organic layer and washed withsaturated NaCl_((aq)). Dried organic layer over anhydrous Na₂SO₄ andconcentrated under reduced pressure. Purified with prep HPLC to affordintermediate 4q.

LC/MS: t_(R)=2.60 min, MS m/z=567.3 [M+1], 565.1 [M−1]; LC/MS system:Thermo LCQ Advantage; Phenomenex Gemini, C₁₈, 5u, 110A, 30×4.6 mm;Buffer A: 0.1% Acetic acid in Water; Buffer B: 0.1% Acetic acid inAcetonitrile; 5-100% Buffer B in 2.5 mins then 100% for 0.9 min @ 2mL/min.

HPLC: t_(R)=3.22 min; HPLC system: Agilent 1100; Phenomenex Gemini, C₁₈,5u, 110A, 50×4.6 mm; Buffer A: 0.05% TFA in Water; Buffer B: 0.05% TFAin Acetonitrile; 2-98% Buffer B in 5 minutes @ 2 mL/min.

Intermediate4r—7-((2S,3S,4S,5R)-3,4-bis(benzyloxy)-5-(benzyloxymethyl)-5-methyltetrahydrofuran-2-yl)pyrrolo[1,24][1,2,4]triazin-4-amine

Intermediate 4q (81 mg, 0.143 mmol) was dissolved in anhydrous DCM (15mL) and stirred under N₂(g) in an ice bath. Added triethylsilane (114μL, 0.715 mmol) in one portion. Added boron trifluoride diethyl etherate(27 μL, 0.215 mmol) dropwise. Stirred for 15 min and then removed icebath. Stirred for 60 min. Added triethylamine (100 μL, 0.715 mmol) andconcentrated under reduced pressure. Dissolved in EtOAc and washed withsaturated NaHCO_(3(aq)) (2×) and then saturated with NaCl_((aq)). Driedorganic over anhydrous Na₂SO₄ and concentrated under reduced pressure.Purified with silica gel column (0-80% EtOAc in hexanes to affordintermediate 4r.

¹H NMR (400 MHz, CDCl₃): δ 7.71 (s, 1H), 7.35-7.10 (m, 16H), 6.82-6.78(m, 1H), 5.57 (d, J=4.4 Hz, 1H), 4.70-4.45 (m, 6H), 4.25-4.15 (m, 2H),3.55-3.40 (m, 2H), 1.42 (s, 3H).

LC/MS: t_(R)=2.75 min, MS m/z=551.4 [M+1]; LC/MS system: Thermo LCQAdvantage

Phenomenex Gemini, C₁₈, 5u, 110A, 30×4.6 mm; Buffer A: 0.1% Acetic acidin Water; Buffer B: 0.1% Acetic acid in Acetonitrile; 5-100% Buffer B in2.5 mins then 100% for 0.9 min @ 2 mL/min.

HPLC: t_(R)=3.57 min; HPLC system: Agilent 1100; Phenomenex Gemini, C₁₈,5u, 110A, 50×4.6 mm; Buffer A: 0.05% TFA in Water; Buffer B: 0.05% TFAin Acetonitrile; 2-98% Buffer B in 5 minutes @ 2 mL/min.

Example 4(2R,3S,4R,5S)-5-(4-aminopyrrolo[1,2-f][1,2,4]triazin-7-yl)-2-(hydroxymethyl)-2-methyltetrahydrofuran-3,4-diol

Intermediate 4r (23 mg, 0.042 mmol) was dissolved into a formicacid/MeOH solution (1:9, 10 mL). Added palladium black and stirred at60° C. for 90 min. Cooled to room temperature and filtered throughCelite. Concentrated filtrate under reduced pressure. Purified with prepHPLC. Concentrated under reduced pressure. Dissolved in NaHCO_(3(aq))and purified with HPLC under neutral condition to afford example 4.

Prep HPLC system: Gilson 215 Liquid Handler; Phenomenex Gemini, C₁₈ 4 u,100×30.0 mm

Buffer A: 0.1% TFA in Water; Buffer B: 0.1% TFA in Acetonitrile; 5-100%Buffer B in 13 minutes @ 20 mL/min.

¹H NMR (400 MHz, CDCl₃): δ 8.01 (s, 1H), 7.41 (d, J=4.8 Hz, 1H), 7.02(d, J=4.8 Hz, 1H), 5.33 (d, J=8 Hz, 1H), 4.53-4.49 (m, 1H), 4.15 (d,J=5.6 Hz, 1H), 3.50 (m, 2H), 1.27 (s, 3H).

LC/MS: t_(R)=0.30 min, MS m/z=281.3 [M+1], 279.0 [M−1]; LC/MS system:Thermo LCQ Advantage; Phenomenex Gemini, C₁₈, 5u, 110A, 30×4.6 mm;Buffer A: 0.1% Acetic acid in

Water; Buffer B: 0.1% Acetic acid in Acetonitrile; 5-100% Buffer B in2.5 mins then 100% for 0.9 min @ 2 mL/min.

HPLC: t_(R)=0.42 min; HPLC system: Agilent 1100; Phenomenex Gemini, C₁₈,5u, 110A, 50×4.6 mm; Buffer A: 0.05% TFA in Water; Buffer B: 0.05% TFAin Acetonitrile; 2-98% Buffer B in 5 minutes @ 2 mL/min.

Intermediate5a—N-(7-((2S,3S,4S,5R)-5-azido-3,4-bis(tert-butyldimethylsilyloxy)-5-((trimethylsilyloxy)methyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

To a solution of crude intermediate 1m,N-(7-((2S,3S,4S)-3,4-bis(tert-butyldimethylsilyloxy)-5-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide,(˜110 mg, ˜0.18 mmol) and azidotrimethysilane (242 μl, 1.84 mmol) indichloromethane (1.5 mL) was added indium (III) bromide (130 mg, 0.369mmol) at RT under an argon atmosphere. After 1 h, the reaction mixturewas quenched with saturated aqueous sodium bicarbonate solution (1 mL).The resulting mixture was partitioned between dichloromethane (20 mL)and saturated aqueous sodium bicarbonate solution (20 mL). The phaseswere split and the aqueous layer was extracted with dichloromethane (20mL). The combined organic layers were dried over anhydrous sodiumsulfate and were concentrated under reduced pressure to affordintermediate 5a that was used directly in the next step without furtherpurification.

LC/MS: t_(R)=3.52 min, MS m/z=712.16 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6 mm

Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.55 min 100% ACN,3.55 min-4.2 min 100%-2% ACN at 2 μl/min.

Intermediate5b—N-(7-((2S,3R,4S,5R)-5-azido-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

To a solution of crude intermediate 5a (˜120 mg, ˜0.168 mmol) in DMF (5mL) was added cesium fluoride (256 mg, 1.68 mmol) at RT. After 25 h, thereaction mixture was diluted with brine (100 mL), and the resultingmixture was extracted with ethyl acetate (3×100 mL). The combinedorganic layers were dried over anhydrous sodium sulfate and wereconcentrated under reduced pressure to afford intermediate 5b that wasused directly in the next step without further purification.

LC/MS: t_(R)=1.40 min, MS m/z=412.17 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6mm; Solvents:

Acetonitrile with 0.1% acetic acid, Water with 0.1% acetic acid;Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05 min 100% ACN, 3.05min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2 μl/min.

HPLC: t_(R)=2.46 min′ HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

Example 5(2R,3S,4R,5S)-5-(4-aminopyrrolo[1,2-f][1,2,4]triazin-7-yl)-2-azido-2-(hydroxymethyl)tetrahydrofuran-3,4-diol

Concentrated ammonium hydroxide (1 mL) was added to a solution of crudeintermediate 5b in methanol (1 mL) at RT. After 2 d, the reactionmixture was concentrated under reduced pressure, and was directlypurified by preparatory HPLC (Phenominex Synergi 4u Hydro-RR80 Å 150×30mm column, 5-100% acetonitrile/water gradient). The fractions containingthe desired were combined and were concentrated under reduced pressure.The residue repurified via SiO2 column chromatography (4 g SiO2Combiflash HP Gold Column, 0-20% methanol/dichloromethane) to affordexample 5.

¹H NMR (400 MHz, CD₃OD) δ 7.79 (s, 1H), 6.86 (d, J=4.5 Hz, 1H), 6.77 (d,J=4.5 Hz, 1H), 5.51 (d, J=6.0 Hz, 1H), 4.63 (t, J=5.8 Hz, 1H), 4.37 (d,J=5.7 Hz, 1H), 3.69 (d, J=12.0 Hz, 1H), 3.59 (d, J=12.0 Hz, 1H).

LC/MS: t_(R)=0.76 min, MS m/z=308.08 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6mm; Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid; Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.2 min 100% ACN, 2.2min-2.4 min 100%-2% ACN, 2.4 min-2.5 min 2% ACN at 2 μl/min.

HPLC: t_(R)=1.287 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.;

TLC: eluent: 20% methanol in dichloromethane, R_(f)=0.4 (UV)

Example 6 (also referred to as TP-1)((2R,3R,4R,5S)-5-(4-aminopyrrolo[1,2-f][1,2,4]triazin-7-yl)-2-cyano-4-fluoro-3-hydroxytetrahydrofuran-2-yl)methyltetrahydrogen triphosphate

Example 3 (15.0 mg, 0.05 mmol) was dried in a flask under vacuumovernight. Trimethylphosphate (0.5 mL) and1,8-bis(dimethylamino)naphthalene (25 mg, 0.12 mmol) were added to theflask and the solution was allowed to stir under N₂ cooled by anice/water bath. Distilled phosphorus oxychloride (10 μL, 0.11 mmol) wasadded and the reaction was allowed to stir for 4 h with cooling.Tributylamine (0.1 ml, 0.42 mmol) and tributylammonium pyrophosphate(0.8 mL of a 0.5 M solution in DMF, 0.4 mmol) were added and thereaction was allowed to stir for an additional 45 min with cooling. Thereaction was quenched with triethylammonium bicarbonate (0.5 M, 5 mL).The solvents were removed by rotary evaporation and the remaining crudemixture was dissolved in 2 mL of water. The product was purified using aSephadex DEAE A-25 column with a linear gradient of 0-1 Mtriethylammonium bicarbonate. The product containing fractions werepooled and concentrated to give example 6 (TP1), which was thendissolved in 1 mL of water to give a 10 mM solution.

MS m/z=532.0 [M−1]

Ion Exchange HPLC Retention time: 12.015 min; Column: DNAPac PA-1004×250 mm SN

Solvent A: milliQ water; Solvent B: 0.5 M tetraethylammonium bromide;Solvent gradient program: equilibrate using 100% A for 10 min, then ramp0-80% B over 14 min.; Flow: 1 mL/min.

Example 7 (also TP2)((2R,3R,4R,5S)-5-(4-aminopyrrolo[1,24][1,2,4]triazin-7-yl)-2-ethynyl-4-fluoro-3-hydroxytetrahydrofuran-2-yl)methyltetrahydrogen triphosphate

Example 2 (16.0 mg, 0.055 mmol) was dried in a flask under vacuumovernight. Trimethylphosphate (0.5 mL) and1,8-bis(dimethylamino)naphthalene (28 mg, 0.13 mmol) were added to theflask and the solution was allowed to stir under N₂ cooled by anice/water bath. Distilled phosphorus oxychloride (11 μL, 0.12 mmol) wasadded and the reaction was allowed to stir for 4 h with cooling.Tributylamine (0.11 mL, 0.42 mmol) and tributylammonium pyrophosphate(0.9 mL of a 0.5 M solution in DMF, 0.45 mmol) were added and thereaction was allowed to stir for an additional 45 min with cooling. Thereaction was quenched with triethylammonium bicarbonate (0.5 M, 5 mL).The solvents were removed by rotary evaporation and the remaining crudemixture was dissolved in 2 mL of water. The product was purified using aSephadex DEAE A-25 column with a linear gradient of 0-1 Mtriethylammonium bicarbonate. The product containing fractions werepooled and concentrated to give example 7 (TP2), which was thendissolved in 1.4 mL of water to give a 10 mM solution.

MS m/z=531.0 [M−1]

Ion Exchange HPLC Retention time: 19.829 min; Column: DNAPac PA-1004×250 mm SN

Solvent A: milliQ water; Solvent B: 0.5 M tetraethylammonium bromide;Solvent gradient program: equilibrate using 100% A for 10 min, then ramp0-80% B over 14 min.; Flow: 1 mL/min

Example 8 (TP3)((2R,3S,4R,5S)-5-(4-aminopyrrolo[1,2-f][1,2,4]triazin-7-yl)-2-cyano-3,4-dihydroxytetrahydrofuran-2-yl)methyltetrahydrogen triphosphate

To a solution of example 1 (5.0 mg, 0.017 mmol) in PO(OMe)₃ (0.6 mL) at0° C. was added POCl₃ (45 mg, 0.29 mmol). The reaction mixture wasstirred at 0° C. for 10 h, at which point Ion-exchange HPLC showedapproximately 50% conversion. A solution of pyrophosphate tributylaminesalts (250 mg) in ACN (0.6 mL) was added, followed by tributylamine (110mg, 0.59 mmol). The reaction mixture was stirred at 0° C. for 0.5 h, andion-exchange HPLC showed the reaction was completed. The reaction wasquenched with triethylammonium bicarbonate buffer (1 M, 5 mL). Thereaction mixture was stirred at RT for 0.5 h, then concentrated andco-evaporated with water twice. The residue was dissolved in H₂O (5 mL)and loaded to a ion-exchange column, eluted with H₂O, then 5-35%triethylammonium bicarbonate buffer (1 M)-H₂O. The product fractionswere combined, concentrated and co-evaporated with H₂O. The residue waspurified by ion-exchange column again to give crude material. ³¹P NMRshowed this material contained impurities, so the material wasrepurified with C-18 column, eluted with 0-15% ACN—H₂O containing 0.05%TEA, and the fractions containing product were combined and concentratedto give 3.6 mg material, which contained only 1.5 equiv of TEA asindicated by ¹H NMR analysis. The material was dissolved in H₂O (1 mL)and triethylammonium bicarbonate buffer (1 M, 0.1 mL) was added. Theresulting mixture was concentrated under reduced pressure andco-evaporated with H₂O twice under reduced pressure to give example 8(TP3), as a tetra-TEA salt.

¹H NMR (400 MHz, D₂O): δ 7.78 (s, 1H), 6.85 (d, J=2.4 Hz, 1H), 6.82 (d,J=2.4 Hz, 1H), 5.51 (d, J=3.0 Hz, 1H), 4.65-4.55 (m, 2H), 4.20-4.08 (m,2H), 3.15-3.00 (m, 24H), 1.18-1.08 (m, 36H).

³¹P NMR (162 MHz, D₂O): δ −6.25 (d, J=52 Hz), −12.21 (d, J=52 Hz),−22.32 (t, J=52 Hz).

MS m/z=530.2 [M−1], 532.1 [M+1]

Example 9 (TP4)((2R,3S,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-azido-3,4-dihydroxytetrahydrofuran-2-yl)methyltetrahydrogen triphosphate

To a solution of example 5 (6.0 mg, 0.019 mmol) in PO(OMe)₃ (0.6 mL) at0° C. was added POCl₃ (45 mg, 0.29 mmol). The reaction mixture wasstirred at 0° C. for 10 h, at which point Ion-exchange HPLC showedapproximately 50% conversion. A solution of pyrophosphate tributylaminesalts (250 mg) in ACN (0.6 mL) was added, followed by tributylamine (110mg, 0.59 mmol). The reaction mixture was stirred at 0° C. for 6 h. Thereaction was quenched with triethylammonium bicarbonate buffer (1 M, 5mL). The reaction mixture was stirred at RT for 0.5 h, then concentratedand co-evaporated with water twice. The residue was dissolved in H₂O (5mL) and loaded to a ion-exchange column, eluted with H₂O, then 5-35%triethylammonium bicarbonate buffer (1 M)-H₂O. The product fractionswere combined, concentrated and co-evaporated with H₂O. The residue waspurified by ion-exchange column again to give crude material. ³¹P NMRshowed this material contained impurities, so the material wasrepurified with ion-exchange column again to give crude material. Thematerial was treated with NaHCO₃ (10 mg) and the mixture wasconcentrated under reduced pressure. The solid residue was dissolved in0.5 mL of H₂O and 40 μL of NaOH (1N) was added. The resulting mixturewas purified with C-18 column, eluted with H₂O, and the fractionscontaining product were combined and concentrated under reduced pressureto afford Example 9 (TP4) as the tetra-sodium salt.

¹H NMR (400 MHz, D₂O): δ 7.76 (s, 1H), 6.88 (d, J=4.3 Hz, 1H), 6.81 (d,J=4.6 Hz, 1H), 5.59 (d, J=5.5 Hz, 1H), 4.60 (t, J=5.6 Hz, 1H), 4.55 (d,J=5.8 Hz, 1H), 3.99 (qd, J=11.2, 5.5 Hz, 3H).

³¹P NMR (162 MHz, D₂O): δ −8.13 (d, J=19.8 Hz), −14.04 (d, J=18.9 Hz),−24.00 (t, J=19.3 Hz).

MS m/z=546.1 [M−1], 547.9 [M+1]

Intermediate PD1a—S-2-hydroxyethyl 2,2-dimethylpropanethioate

To a solution of 2-thioethanol (3.50 mL, 50.0 mmol) and triethylamine(7.02 mL, 50.0 mmol) in CH₂Cl₂, that has been cooled to −78° C. wasadded pivalyl chloride (6.15 mL, 50.0 mmol) dropwise over 30 min. Thereaction was allowed to warm slowly to room temperature and progressionwas monitored by TLC. After 30 min, the reaction was determined to becomplete and was quenched with water. The layers were separated and theaqueous was washed with CH₂Cl₂. The organics were combined and driedover sodium sulfate. The solids were filtered and the solvent wasremoved under reduced pressure. The crude was purified by silica gelchromatography 0-50% EtOAc/hexanes to afford intermediate PD1a.

¹H NMR (400 MHz, DMSO-d₆) δ 4.89 (t, J=5.5 Hz, 1H), 3.49-3.36 (m, 2H),2.86 (t, J=6.7 Hz, 2H), 1.14 (s, 9H).

Take up phosphorous oxychloride (281 μL, 3.08 mmol) in CH₂Cl₂ (5 mL) andcool the solution to −78° C. Take up the thioester PD1a (1.00 g, 6.17mmol) in CH₂Cl₂(5 mL) and add slowly to the POCl₃ solution. Next add TEA(891 μL, 6.16 mmol) dropwise and allow to stir cold for 30 min. Thenwarm to room temperature and allow to stir for 2 h. Add thep-nitrophenol (428 mg, 3.08 mmol) in one portion followed by a slowaddition of TEA (449 μL, 3.08 mmol). Stir at room temperature for 30min. TLC (70:30 Hexanes/EtOAC) showed only one spot, but LC/MS had twopeaks (product and bis-p-nitrophenolate). The solution was diluted withether and the solids were removed by filtration and discarded. Themother liquor was concentrated and purified by silica gel chromatographyto give a mixture of product and bis-p-nitrophenolate. The mixture wasthen repurified by HPLC to afford intermediate PD1b,S,S′-2,2′-((4-nitrophenoxy)phosphoryl)bis(oxy)bis(ethane-2,1-diyl)bis(2,2-dimethylpropanethioate).

¹H NMR (400 MHz, CDCl₃) δ 8.29-8.21 (m, 2H), 7.46-7.36 (m, 2H), 4.23 (brq, J=7.7 Hz, 4H), 3.16 (br t, J=6.7 Hz, 4H), 1.23 (s, 18H).

³¹P NMR (162 MHz, CDCl₃) δ −7.72 (s).

Example 10 (also referred to as PD1)S,S′-2,2′-((((2R,3S,4R,5S)-5-(4-aminopyrrolo[1,2-f][1,2,4]triazin-7-yl)-2-cyano-3,4-dihydroxytetrahydrofuran-2-yl)methoxy)phosphoryl)bis(oxy)bis(ethane-2,1-diyl)bis(2,2-dimethylpropanethioate).

Example 1 (6.0 mg, 0.02 mmol) was dissolved in NMP (0.1 mL), and THF(0.2 mL) was added. tert-Butyl magnesium chloride (1.0 M solution inTHF, 0.031 mL, 0.031 mmol) was then added at RT under an argonatmosphere. After 10 min, a solution of intermediate PD1b (15.7 mg,0.031 mmol) in THF (0.1 mL) was added and the resulting mixture waswarmed to 50° C. After 5 h, the resulting residue was purified bypreparatory HPLC (Phenominex Synergi 4u Hydro-RR 80 Å 150×30 mm column,40-100% acetonitrile/water gradient). The fractions containing thedesired product were combined and were lyophilized to afford example 10(PD1).

¹H NMR (400 MHz, CDCl₃) δ 7.82 (s, 1H), 6.69 (d, J=4.5 Hz, 1H), 6.64 (d,J=4.5 Hz, 1H), 5.56 (d, J=3.4 Hz, 1H), 4.61 (br s, 2H), 4.45-4.32 (m,2H), 4.22-4.06 (m, 4H), 3.13 (dt, J=11.7, 6.7 Hz, 4H), 1.23 (s, 9H),1.21 (s, 9H).

³¹P NMR (162 MHz, CDCl₃) δ −2.34 (s).

LC/MS: t_(R)=1.70 min, MS m/z=660.02 [M+1],; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6 mm

Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05 min 100% ACN,3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2 μl/min.

HPLC: t_(R)=3.204 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA

Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at 2 mL/min.

Example 11 (PD2)S,S′-2,2′-((((2R,3R,4R,5S)-5-(4-aminopyrrolo[1,2-f][1,2,4]triazin-7-yl)-2-cyano-4-fluoro-3-hydroxytetrahydrofuran-2-yl)methoxy)phosphoryl)bis(oxy)bis(ethane-2,1-diyl)bis(2,2-dimethylpropanethioate)

Example 3 (10.5 mg, 0.036 mmol) was dissolved in NMP (0.1 mL), and THF(0.1 mL) was added. tert-Butyl magnesium chloride (1.0 M solution inTHF, 0.054 mL, 0.054 mmol) was then added at RT under an argonatmosphere. After 10 min, a solution of intermediate PD1b (27.3 mg,0.054 mmol) in THF (0.1 mL) was added and the resulting mixture waswarmed to 50° C. After 24 h, the resulting residue was purified bypreparatory HPLC (Phenominex Synergi 4u Hydro-RR 80 Å 150×30 mm column,40-100% acetonitrile/water gradient). The fractions containing thedesired product were combined and were lyophilized to afford example 11(PD2).

¹H NMR (400 MHz, CDCl₃) δ 7.94 (s, 1H), 6.75 (d, J=4.5 Hz, 1H), 6.67 (d,J=4.5 Hz, 1H), 5.77 (dd, J=27.8, 1.4 Hz, 1H), 5.43 (ddd, J=55.2, 4.9,1.3 Hz, 1H), 4.93 (dd, J=21.2, 4.9 Hz, 1H), 4.49 (dd, J=11.3, 7.8 Hz,1H), 4.40 (dd, J=11.3, 7.8 Hz, 1H), 4.10 (ddt, J=15.9, 8.0, 6.7 Hz, 4H),3.16-3.04 (m, 4H), 1.23 (s, 9H), 1.21 (s, 9H).

³¹P NMR (162 MHz, CDCl₃) δ −2.10 (s).

¹⁹F NMR (376 MHz, CDCl₃) δ −191.64 (ddd, J=55.0, 27.8, 21.3 Hz).

LC/MS: t_(R)=1.85 min, MS m/z=662.03 [M+1],; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6mm; Solvents:

Acetonitrile with 0.1% acetic acid, Water with 0.1% acetic acid;Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05 min 100% ACN, 3.05min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2 μl/min.

HPLC: t_(R)=3.385 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

Intermediate PD3c—(2S)-2-ethylbutyl2-((4-nitrophenoxy)(phenoxy)phosphorylamino)propanoate

Dissolved phenyl dichlorophosphate PD3a (1.5 mL, 10 mmol) in 30 mLanhydrous DCM and stirred under N₂(g) in an ice bath. Added amino esterHCl salt PD3b, (S)-2-ethylbutyl 2-aminopropanoate hydrochloride,(prepared according to Eur. J. Med. Chem. 2009, 44, 3765-3770, 2.1 g, 10mmol) in one portion. Added TEA (3 mL, 22 mmol) dropwise. Stirred for 1h at 0° C. Added p-nitrophenol (1.4 g, 10 mmol) in one portion and TEA(1.5 mL, 11 mmol). The reaction mixture was then stirred at roomtemperature for 16 h. Diluted with DCM and washed with saturatedNaHCO_(3(aq)). Dried organic over anhydrous Na₂SO₄ and concentratedunder reduced pressure. Purified with silica gel column (0-15% EtOAc inhexanes) to afford intermediate PD3c.

¹H NMR (400 MHz, CDCl₃) δ 8.23 (d, J=8.8 Hz, 2H), 7.41-7.30 (m, 4H),7.25-7.19 (m, 3H), 4.10-4.00 (m, 3H), 3.90-3.83 (m, 1H), 1.55-1.45 (m,1H), 1.42-1.31 (m, 7H), 0.87 (t, J=7.2 Hz, 6H).

³¹P NMR (162 MHz, CDCl₃) δ −3.04 (s), −3.10 (s).

LC/MS: t_(R)=2.87 min, MS m/z=451.1 [M+1], 449.0 [M−1]; LC/MS system:Thermo LCQ Advantage; Phenomenex Gemini, C₁₈, 5u, 110A, 30×4.6 mm;Buffer A: 0.1% Acetic acid in Water; Buffer B: 0.1% Acetic acid inAcetonitrile; 5-100% Buffer B in 2.5 mins then 100% for 0.9 min @ 2mL/min.

HPLC: t_(R)=4.40 min; HPLC system: Agilent 1100; Phenomenex Gemini, C₁₈,5u, 110A, 50×4.6 mm; Buffer A: 0.05% TFA in Water; Buffer B: 0.05% TFAin Acetonitrile; 2-98% Buffer B in 5 minutes @ 2 mL/min.

Example 12 (PD3) (2S)-2-ethylbutyl2-((((2R,3R,4R,5S)-5-(4-aminopyrrolo[1,2-f][1,2,4]triazin-7-yl)-2-cyano-4-fluoro-3-hydroxytetrahydrofuran-2-yl)methoxy)(phenoxy)phosphorylamino)propanoate.

Dissolved example 3 (15 mg, 0.051 mmol) in anhydrous DMF (1 mL) andstirred under N₂(g). Dissolved p-nitrophenylphosphoamidate PD3c (35 mg,0.077 mmol) in anhydrous DMF (0.5 mL) and added to the reaction mixturein one portion. Added tBuMgCl in THF (1M in THF, 77 μL, 0.077 mmol)dropwise. Stirred for 2 h. Added more p-nitrophenylphosphoamidate (35 mgin 0.5 mL anhydrous DMF) and more tBuMgCl (1 M in THF, 50 μL, 0.050mmol). Stirred for 2 h. Added more p-nitrophenylphosphoamidate (35 mg in0.5 mL anhydrous DMF) and more tBuMgCl solution (1M in THF, 50 μL, 0.050mmol). Stirred for 16 hours. Diluted with EtOAc and washed withsaturated NaHCO_(3(aq)) (3×). Washed with saturated NaCl_((aq)) anddried organic over anhydrous Na₂SO₄. Concentrated under reducedpressure. Purified with silica gel column (0-5% MeOH in DCM). Combinedfractions and concentrated under reduced pressure. Purified withpreparatory HPLC with TFA as modifier to afford example 12 (PD3).

Prep HPLC system: Gilson 215 Liquid Handler; Phenomenex Gemini, C₁₈ 4 u,100×30.0 mm

Buffer A: 0.1% TFA in Water; Buffer B: 0.1% TFA in Acetonitrile; 5-100%Buffer Bin 13 minutes @ 20 mL/min.

¹H NMR (400 MHz, CDCl₃) δ 7.89 (s, 1H), 7.31-7.13 (m, 6H), 6.80-6.75 (m,1H), 5.80-5.70 (m, 1H), 5.35-5.20 (m, 1H), 4.80-4.62 (m, 1H), 4.60-4.45(m, 2H), 4.35-4.10 (m, 1H), 4.06-3.96 (m, 3H), 1.49-1.28 (m, 8H),0.90-0.82 (m, 6H).

³¹P NMR (162 MHz, CDCl₃) δ 2.36 (s), 2.22 (s).

HPLC: t_(R)=3.00 min; HPLC system: Agilent 1100; Phenomenex Gemini, C₁₈,5u, 110A, 50×4.6 mm; Buffer A: 0.05% TFA in Water; Buffer B: 0.05% TFAin Acetonitrile; 2-98% Buffer B in 5 minutes @ 2 mL/min.

LC/MS: t_(R)=2.39 min, MS m/z=605.1 [M+1], 603.0 [M−1]; LC/MS system:Thermo LCQ Advantage; Phenomenex Gemini, C₁₈, 5u, 110A, 30×4.6 mm;Buffer A: 0.1% Acetic acid in Water; Buffer B: 0.1% Acetic acid inAcetonitrile; 5-100% Buffer B in 2.5 mins then 100% for 0.9 min @ 2mL/min.

Intermediate6a—N-(7-((2S,3S,4R,5R)-4-(tert-butyldimethylsilyloxy)-5-((tert-butyldimethylsilyloxy)methyl)-3-fluoro-5-vinyltetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide

Intermediate 2g,N-(7-((2S,3S,4R,5R)-4-(tert-butyldimethylsilyloxy)-5-((tert-butyldimethylsilyloxy)methyl)-3-fluoro-5-(hydroxymethyl)tetrahydrofuran-2-yl)pyrrolo[1,2-f][1,2,4]triazin-4-yl)benzamide,(220 mg, 0.35 mmol) was dissolved in 5 mL of anhydrous DMSO and stirredunder N₂(g). Added EDCl (100 mg, 0.52 mmol) and then TFA-Pyridine (34mg, 0.18 mmol). Stirred for 1 h. Added more EDCl (100 mg, 0.52 mmol) andstirred for 1 h. Monitoring by LC/MS showed starting material alcoholremained. Added more EDCl (100 mg, 0.52 mmol) and stirred for 1 h.Monitoring by LC/MS showed that the reaction reached full conversion.Diluted with ethyl acetate and washed with saturated NaHCO_(3(aq)) (2×)and then saturated NaCl_((aq)). Dried organic layer over anhydrousNa₂SO₄ and concentrated under reduced pressure. Purified with silica gelcolumn (0-20% EtOAc in hexanes). Combined fractions and concentratedunder reduced pressure to give aldehyde as solid. Suspended Methyltriphenylphosphonium bromide (500 mg, 1.40 mmol) in 10 mL anhydrous THFand stirred at −78° C. under Ar_((g)). Added 2.5 M n-butyllithiumsolution in hexane (560 μL, 1.40 mmol) dropwise. Stirred reactionmixture in an ice bath for 1 h to give a yellow mixture. Dissolved aboveprepared aldehyde in 5 mL of anhydrous THF and added to reactiondropwise. Removed ice bath and let reaction warmed to RT. Stirred for 3h at RT. Added saturated aqueous NH₄Cl solution and extracted with ethylacetate. Washed organic extract with saturated NaHCO_(3(aq)) and thensaturated NaCl_((aq)). Dried organic over anhydrous Na₂SO₄ andconcentrated under reduced pressure. Purified with silica gel column(0-20% EtOAc in hexanes) to afford intermediate 6a.

¹H NMR (400 MHz, DMSO-d6) δ 8.22 (br s, 1H), 8.03 (br s, 2H), 7.58 (dt,J=40.4, 7.4 Hz, 3H), 7.12 (d, J=4.7 Hz, 1H), 6.97 (s, 1H), 6.01 (dd,J=17.5, 10.9 Hz, 1H), 5.58 (d, J=22.8 Hz, 1H), 5.46 (dd, J=17.5, 2.1 Hz,1H), 5.25 (dd, J=11.0, 2.0 Hz, 1H), 5.14 (ddd, J=55.4, 4.9, 2.7 Hz, 1H),4.61 (dd, J=20.8, 4.8 Hz, 1H), 3.63-3.40 (m, 2H), 0.89 (s, 9H), 0.84 (s,9H), 0.09 (d, J=8.4 Hz, 6H), 0.00 (d, J=14.1 Hz, 6H).

¹⁹F NMR (376 MHz, DMSO-d6) δ −191.86 (d, J=56.8 Hz).

MS m/z=627.3 [M+1].

Example 13(2R,3R,4R,5S)-5-(4-aminopyrrolo[1,2-f][1,2,4]triazin-7-yl)-4-fluoro-2-(hydroxymethyl)-2-vinyltetrahydrofuran-3-ol

Intermediate 6a (146 mg, 0.23 mmol) was dissolved into THF (10 mL) andthe resulting solution was stirred in an ice bath. Added 1M TBAFsolution in THF (700 μL, 0.70 mmol) and stirred for 2 h. Diluted withEtOAc and washed with saturated NaCl_((aq)) (5×). Dried organic layerover anhydrous Na₂SO₄ and concentrated under reduced pressure. Dissolvedin 7 M ammonia in MeOH (7 mL) and stirred for 18 h. Concentratedreaction under reduced pressure. Purified with C₁₈ preparatory HPLC withTFA as modifier. Combined fractions and concentrated under reducedpressure. Dissolved in NaHCO_(3(aq)) and repurified with preparatoryHPLC under neutral condition. Combined fractions and freeze-dried toafford example 13.

¹H NMR (400 MHz, D₂O) δ 7.54 (s, 1H), 6.62-6.49 (m, 2H), 5.98-5.79 (m,1H), 5.55-5.36 (m, 2H), 5.31 (d, J=11.1 Hz, 1H), 5.11 (ddd, J=54.8, 5.2,2.9 Hz, 1H), 4.42 (dd, J=20.6, 4.8 Hz, 1H), 3.62-3.43 (m, 2H).

¹⁹F NMR (376 MHz, D₂O) 5-193.23 (dd, J=54.7, 44.2 Hz).

MS m/z=295.2 [M+1]

Example 14(2R,3R,4R,5S)-5-(4-aminopyrrolo[1,24][1,2,4]triazin-7-yl)-2-ethyl-4-fluoro-2-(hydroxymethyl)tetrahydrofuran-3-ol

Example 13 (5 mg, 0.017 mmol) was dissolved into methanol (2 mL). 10%Pd/C Degussa Catalyst (2 mg) was then added and the resulting mixturewas stirred under atmosphere of hydrogen gas. After 40 min, theresulting mixture was filtered to remove Pd/C and the filtrate wasconcentrated under reduced pressure. The residue was dissolved in waterand freeze-dried to afford example 14.

¹H NMR (400 MHz, D₂O) δ 7.67 (s, 1H), 6.79-6:55 (m, 2H), 5.54-5.12 (m,2H), 4.46 (dd, J=15.1, 5.5 Hz, 1H), 3.65-3.44 (m, 2H), 1.89-1.44 (m,2H), 0.84 (t, J=7.6 Hz, 3H).

¹⁹F NMR (376 MHz, D₂O) δ −197.62 (ddd, J=54.5, 20.6, 15.0 Hz).

MS m/z=297.3 [M+1].

Example 15 (PD4)S,S′-2,2′-((((2R,3R,4R,5S)-5-(4-aminopyrrolo[1,2-f][1,2,4]triazin-7-yl)-4-fluoro-3-hydroxy-2-vinyltetrahydrofuran-2-yl)methoxy)phosphoryl)bis(oxy)bis(ethane-2,1-diyl)bis(2,2-dimethylpropanethioate)

Example 13 (5 mg, 0.017 mmol) was dissolved into anhydrous DMF (0.5 mL).Added p-nitro-phenonate (13 mg, 0.026 mmol) in one portion. Added 1Mt-butylmagnesium chloride in THF (25 μL, 0.026 mmol) dropwise. Stirredfor 1 h. Warmed to 50° C. and stirred for 2 h. Added morep-nitro-phenonate (13 mg, 0.026 mmol) and stirred for 2 h. Added more 1Mt-butylmagnesium chloride in THF (25 μL, 0.026 mmol) and stirred for 16h at 50° C. Cooled to RT. The resulting mixture was purified directly bypreparatory HPLC column and eluted with linear gradient 0-100% ACN inwater to afford example 15 (PD4).

¹H NMR (400 MHz, CD₃OD) δ 7.84 (s, 1H), 6.92 (d, J=4.5 Hz, 1H), 6.80 (d,J=4.5 Hz, 1H), 6.10 (dd, J=17.4, 10.9 Hz, 1H), 5.67 (dd, J=5.8, 1.9 Hz,1H), 5.61 (s, 1H), 5.45-5.35 (m, 1H), 5.15 (ddd, J=55.6, 5.0, 2.2 Hz,1H), 4.65 (dd, J=22.5, 5.1 Hz, 1H), 4.13 (dd, J=11.1, 5.2 Hz, 1H),4.08-3.95 (m, 5H), 3.06 (dd, J=7.0, 6.1 Hz, 4H), 1.21 (s, 9H), 1.18 (s,9H).

¹⁹F NMR (376 MHz, CD₃OD) δ 192.99 (td, J=55.7, 23.6 Hz).

MS m/z=663.0 [M+1].

Example 16 (PD5) (2S)-2-ethylbutyl2-(((((2R,3S,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-azido-3,4-dihydroxytetrahydrofuran-2-yl)methoxy)(phenoxy)phosphoryl)amino)propanoate

Example 5 (5 mg, 0.016 mmol) was dissolved in anhydrousN-methyl-2-pyrrolidone (0.2 mL) and THF (0.1 mL) was added under anargon atmosphere. tert-Butyl magnesium chloride (1 M in THF, 24 μL,0.024 mmol) was then added at RT, and white solids precipitated. After 5min, a solution of p-nitrophenylphosphoamidate PD3c (15 mg, 0.032 mmol)in THF (0.1 mL) was added to the reaction mixture in one portion, andthe resulting mixture was heated to 50° C. After 3.5 h, the reactionmixture was allowed to cool to RT and was stirred for 18 h.p-Nitrophenylphosphoamidate PD3c (50 mg, 0.111 mmol) and tert-butylmagnesium chloride (1M in THF, 24 μL, 0.024 mmol) were then added andthe reaction mixture was stirred for an additional 5 d. The resultingresidue was then purified directly by preparatory HPLC (PhenominexSynergi 4u Hydro-RR 80A 150×30 mm column, 40-100% acetonitrile/watergradient). The fractions containing the desired product were combinedand were lyophilized to afford example 16 (PD5) (2:1 diastereomericmixture).

¹H NMR (400 MHz, CDCl₃) δ 7.88 (br s, 1H), 7.33-7.22 (br m, 2H),7.22-7.10 (br m, 3H), 6.69 (br d, J=4.4 Hz, 1H), 6.61 (br d, J=4.5 Hz,1H), 5.64-5.56 (m, 1H), 4.54 (d, J=6.3 Hz, 1H), 4.50-4.20 (m, 3H),4.11-3.94 (m, 3H), 3.90-3.76 (m, 1H), 1.49 (s, J=6.2 Hz, 1H), 1.40-1.24(m, 7H), 0.86 (t, J=7.4 Hz, 6H).

³¹P NMR (162 MHz, CDCl₃) δ 2.68 (s), 2.56 (s).

LC/MS: t_(R)=1.70 min, MS m/z=619.09 [M+1]; LC system: Thermo Accela1250 UHPLC.

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×4.6mm; Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1% aceticacid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05 min 100% ACN,3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2 μl/min.

HPLC: t_(R)=3.010 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

Example 17 (TP5)((2R,3R,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-4-fluoro-3-hydroxy-2-vinyltetrahydrofuran-2-yl)methyltetrahydrogen triphosphate

To a solution of example 13 (6.0 mg, 0.020 mmol) in PO(OMe)₃ (0.6 mL) at0° C. was added POCl₃ (50 mg, 0.32 mmol). The reaction mixture wasstirred at 0° C. for 6 h, at which point Ion-exchange HPLC showedapproximately 90% conversion. A solution of pyrophosphate tributylaminesalts (250 mg) in ACN (0.6 mL) was added, followed by tributylamine (110mg, 0.59 mmol). The reaction mixture was stirred at 0° C. for 1 h. Thereaction was quenched with triethylammonium bicarbonate buffer (1 M, 5mL). The reaction mixture was stirred at RT for 0.5 h, then concentratedand co-evaporated with water twice. The residue was dissolved in H₂O (5mL) and loaded to a ion-exchange column, eluted with H₂O, then 5-35%triethylammonium bicarbonate buffer (1 M)-H₂O. The product fractionswere combined, concentrated and co-evaporated with H₂O. The solidresidue was dissolved in 3 mL of H₂O and 100 μL of NaOH (1 N) was added.The resulting mixture was purified with C-18 column, eluted with H₂O,and the fractions containing product were combined and concentratedunder reduced pressure to afford Example 17 (TP5) as the tetra-sodiumsalt.

¹H NMR (400 MHz, D₂O): δ 7.74 (s, 1H), 6.89 (d, J=4.4 Hz, 1H), 6.81 (d,J=4.6 Hz, 1H), 6.00 (dd, J=17.4, 11.1 Hz, 1H), 5.72 (d, J=23.3 Hz, 1H),5.49 (d, J=16.9 Hz, 1H), 5.32 (d, J=11.1 Hz, 1H), 5.14 (dd, J=54.0, 4.6Hz, 1H), 4.72 (dd, J=23.7, 4.5 Hz, 1H), 4.09 (dd, J=11.3, 5.8 Hz, 1H),3.79 (dd, J=11.6, 3.8 Hz, 1H).

³¹P NMR (162 MHz, D₂O): δ −8.38 (d, J=20.5 Hz), −13.67 (d, J=19.3 Hz),−24.20 (t, J=19.9 Hz).

¹⁹F NMR (376 MHz, CDCl₃) δ −194.58 (dt, J=55.0, 23.8 Hz).

MS m/z=533.0[M−1], 535.0 [M−1].

Example 18 (TP6)((2R,3R,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-ethyl-4-fluoro-3-hydroxytetrahydrofuran-2-yl)methyltetrahydrogen triphosphate

To a solution of example 14 (5.0 mg, 0.017 mmol) in PO(OMe)₃ (0.6 mL) at0° C. was added POCl₃ (45 mg, 0.30 mmol). The reaction mixture wasstirred at 0° C. for 6 h, at which point Ion-exchange HPLC showedapproximately 90% conversion. A solution of pyrophosphate tributylaminesalts (250 mg) in ACN (0.6 mL) was added, followed by tributylamine (110mg, 0.59 mmol). The reaction mixture was stirred at 0° C. for 1 h. Thereaction was quenched with triethylammonium bicarbonate buffer (1 M, 5mL). The reaction mixture was stirred at RT for 0.5 h, then concentratedand co-evaporated with water twice. The residue was dissolved in H₂O (5mL) and loaded to a ion-exchange column, eluted with H₂O, then 5-35%triethylammonium bicarbonate buffer (1 M)-H₂O. The product fractionswere combined, concentrated and co-evaporated with H₂O. The solidresidue was dissolved in 3 mL of H₂O and 100 μL of NaOH (1 N) was added.The resulting mixture was purified with C-18 column, eluted with H₂O,and the fractions containing product were combined and concentratedunder reduced pressure to afford 18 (TP6) as the tetra-sodium salt.

¹H NMR (400 MHz, D₂O): δ 7.73 (s, 1H), 6.86 (d, J=4.6 Hz, 1H), 6.80 (d,J=4.6 Hz, 1H), 5.60 (dd, J=21.9, 3.5 Hz, 1H), 5.23 (dt, J=55.2, 4.2 Hz,1H), 4.65 (dd, J=20.6, 5.3 Hz, 1H), 4.08-3.84 (m, 3H), 1.83 (dq, J=14.4,7.4, 6.9 Hz, 1H), 1.62 (dq, J=15.0, 7.5 Hz, 1H), 0.87 (t, J=7.5 Hz, 3H).

³¹P NMR (162 MHz, D₂O): −5.72 (d, J=20.2 Hz), −10.81 (d, J=19.3 Hz),−21.60 (t, J=19.8 Hz).

¹⁹F NMR (376 MHz, CDCl₃) δ −194.77 (dt, J=55.2, 21.2 Hz).

MS m/z=535.1[M−1], 536.9.0 [M+1].

Intermediate8a—N-(7-((2S,3R,4R,5S)-3-fluoro-4-hydroxy-5-(iodomethyl)tetrahydrofuran-2-yl)pyrrolo[2,1-f][1,2,4]triazin-4-yl)benzamide

To an argon purged flask was added 2b (68 mg, 0.183 mmol) in DMF (2 mL)followed by methyltriphenoxyphosphonium iodide (124 mg, 0.274 mmol). Thereaction was allowed to stir at room temperature for 5 min wherecomplete conversion to product was observed by LCMS. The reaction wasquenched with methanol and solvents were removed under reduced pressure.The crude material was partitioned between EtOAc and H₂O. The organicswere separated and washed with brine. The resulting material was driedover Na₂SO₄, filtered and solvent removed under reduced pressure. Thecrude material was purified by silica gel chromatography (20-100%EtOAc/Hexanes) to afford intermediate 8a.

¹H NMR (400 MHz, DMSO-d₆) δ 8.17 (m, 3H), 7.63 (t, J=7.4 Hz, 1H), 7.53(t, J=7.6 Hz, 2H), 7.17-6.96 (m, 2H), 5.74 (s, 1H), 5.60 (d, J=24.9 Hz,1H), 5.19 (ddd, J=54.6, 4.5, 2.1 Hz, 1H), 4.09-3.92 (m, 1H), 3.72 (t,J=6.4 Hz, 1H), 3.63 (dd, J=11.0, 3.4 Hz, 1H), 3.44 (dd, J=11.0, 5.9 Hz,1H).

¹⁹F NMR (376 MHz, DMSO-d₆) δ −194.23 (m).

LC/MS: t_(R)=1.13 min, MS m/z=483.23 [M+1]

LC system: Thermo Accela 1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80 min 100% ACN, 1.8min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN.

Intermediate8b—(3R,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-4-fluoro-2-methylenetetrahydrofuran-3-ol

Intermediate 8a (80 mg, 0.166 mmol) was dissolved into THF. DBU (0.074mL, 0.498 mmol) was added in one portion. The reaction was then heatedto 60° C. in an oil bath for 16 h. The reaction was cooled to roomtemperature and the solvent was removed under reduced pressure. Thecrude material was purified by silica gel chromatography (0-70%EtOAc/Hex) to afford intermediate 8b.

¹H NMR (400 MHz, DMSO-d₆) δ 8.34-8.05 (m, 3H), 7.63 (t, J=7.4 Hz, 1H),7.53 (t, J=7.6 Hz, 2H), 7.13 (d, J=4.7 Hz, 1H), 6.85 (d, J=4.4 Hz, 1H),5.97-5.82 (m, 2H), 5.39-5.13 (m, 1H), 4.89-4.69 (m, 1H), 4.38 (d, J=2.1Hz, 1H), 4.16 (t, J=1.8 Hz, 1H).

¹⁹F NMR (376 MHz, DMSO-d₆) δ −198.14 (ddd, J=53.9, 24.7, 20.9 Hz).

LC/MS: t_(R)=1.05 min, MS m/z=355.15 [M+1]

LC system: Thermo Accela 1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80 min 100% ACN, 1.8min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN.

Intermediate8c—(2S,3R,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-azido-4-fluoro-2-(iodomethyl)tetrahydrofuran-3-ol

Benzyltrimethylammonium chloride (55 mg, 0.296 mmol) and sodium azide(19.3 mg, 0.296 mmol) were dissolved into ACN (1 mL). The resultingmixture was stirred at RT overnight and was then filtered and added viasyringe to a solution of intermediate 8b (50 mg, 0.141 mmol) in THF (1mL). N-methylmorpholine (0.078 mL, 0.706 mmol) was then added followedby the dropwise addition of a solution of iodine (65 mg, 0.25 mmol) inTHF (1 mL). After 15 min, N-acetyl cysteine was added until theevolution of gas was no longer observable. Then saturated aqueous sodiumthiosulfate was added until the solution was light yellow. The crudemixture was partitioned between EtOAc and H₂O. The phases were split andthe organic layer was dried over sodium sulfate, filtered, andconcentrated under reduced pressure. The crude material was purified bysilica gel chromatography (0-60% EtOAc/Hex) to afford intermediate 8c.

¹H NMR (400 MHz, DMSO-d₆) δ 8.31-8.05 (m, 3H), 7.63 (t, J=7.5 Hz, 1H),7.53 (t, J=7.6 Hz, 2H), 7.14 (d, J=4.6 Hz, 1H), 7.04 (s, 1H), 6.34 (d,J=6.9 Hz, 1H), 5.80 (d, J=23.7 Hz, 1H), 5.55-5.31 (m, 1H), 4.62 (dt,J=21.9, 5.9 Hz, 1H), 3.78-3.56 (m, 2H).

¹⁹F NMR (376 MHz, DMSO-d₆) δ −194.44 (dt, J=54.7, 22.8 Hz).

LC/MS: t_(R)=1.19 min, MS m/z=524.09 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80 min 100% ACN, 1.8min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN.

Intermediate8d—(2S,3R,4S,5S)-5-(4-aminopyrrolo[2,1f-][1,2,4]triazin-7-yl)-2-azido-4-fluoro-2-(iodomethyl)tetrahydrofuran-3-ylacetate

To a solution of intermediate 8c (40 mg, 0.076 mmol) in THF (1 mL) wasadded acetic anhydride (0.009 mL, 0.092 mmol) followed by DMAP (10 mg,0.082 mmol) at RT. After 15 min, the reaction mixture was quenched withmethanol, and the resulting mixture concentrated under reduced pressure.The crude was purified by silica gel chromatography (0-50% EtOAc/Hex) toafford intermediate 8d.

¹H NMR (400 MHz, CDCl₃) δ 8.15-8.02 (m, 3H), 7.62 (t, J=7.3 Hz, 1H),7.53 (t, J=7.6 Hz, 2H), 7.44 (d, J=4.6 Hz, 1H), 7.00 (d, J=4.6 Hz, 1H),5.95-5.80 (m, 1H), 5.70-5.43 (m, 2H), 3.71 (d, J=11.3 Hz, 1H), 3.60 (d,J=11.3 Hz, 1H), 2.25 (s, 3H).

¹⁹F NMR (376 MHz, CDCl₃) δ −192.78 (ddd, J=55.7, 24.6, 18.5 Hz).

LC/MS: t_(R)=1.35 min, MS m/z=566.14 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80 min 100% ACN, 1.8min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN.

Intermediate8e—((2R,3R,4S,5S)-3-acetoxy-2-azido-5-(4-benzamidopyrrolo[2,1-f][1,2,4]triazin-7-yl)-4-fluorotetrahydrofuran-2-yl)methylbenzoate

To a solution of intermediate 8d (30 mgs, 0.053 mmol) in DMF (2 mL) wasadded 15-Crown-5 (0.105 mL, 0.531 mmol) and sodium benzoate (77 mg,0.531 mmol) at RT. The reaction was then heated to 105° C. After 30 h,the reaction mixture was allowed to RT and was partitioned between 5%LiCl_((aq)) and EtOAc. The phases were split and the aqueous phase waswashed with EtOAc (2×). The combined organic extracts were dried overanhydrous sodium sulfate, and were concentrated under reduced pressure.The crude residue was purified by silica gel chromatography (0-60%EtOAc/Hex) to afford intermediate 8e.

¹H NMR (400 MHz, CDCl₃) δ 8.25-7.97 (m, 4H), 7.69-7.40 (m, 6H), 7.36 (d,J=4.7 Hz, 1H), 6.95-6.80 (m, 1H), 5.90 (d, J=25.0 Hz, 1H), 5.65 (d,J=1.9 Hz, 1H), 5.62-5.48 (m, 1H), 4.69 (dd, J=79.3, 12.0 Hz, 2H), 2.20(s, 3H).

¹⁹F NMR (376 MHz, CDCl₃) δ −192.57 (ddd, J=53.9, 25.1, 22.0 Hz).

LC/MS: t_(R)=1.45 min, MS m/z=560.14 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80 min 100% ACN, 1.8min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN.

Example 19(2R,3R,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-azido-4-fluoro-2-(hydroxymethyl)tetrahydrofuran-3-ol

To intermediate 8e (24 mg, 0.043 mmol) was added 7N NH₃ in CH₃OH (2 mL)at RT. After 16 h, the resulting mixture was concentrated under reducedpressure. The crude residue was purified by reverse phase HPLC withoutacid modifier to afford example 19.

¹H NMR (400 MHz, Methanol-d₄) δ 7.81 (s, 1H), 6.85 (d, J=4.5 Hz, 1H),6.80 (d, J=4.5 Hz, 1H), 5.80 (dd, J=24.7, 1.9 Hz, 1H), 5.22 (ddd,J=55.6, 5.1, 1.9 Hz, 1H), 4.63 (dd, J=22.9, 5.1 Hz, 1H), 3.81 (d, J=12.1Hz, 1H), 3.70 (d, J=12.2 Hz, 1H).

¹⁹F NMR (376 MHz, Methanol-d₄) δ −195.30 (ddd, J=55.5, 24.6, 22.9 Hz).

LC/MS: t_(R)=0.61 min, MS m/z=310.02 [M+1]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm

Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid

Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80 min 100% ACN, 1.8min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN.

Intermediate9b—((3aR,5R,6S,6aR)-6-(benzyloxy)-5-((benzyloxy)methyl)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl)methanol

((3aR,6S,6aR)-6-(benzyloxy)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole-5,5-diyl)dimethanol(9a, Purchased from Carbosynth, 10.0 g, 32.2 mmol) was added to asolution of sodium hydride (60% by wt, 1.55 g, 38.7 mmol) in THF (100mL) at 0° C. under an argon atmosphere. After 10 min, benzyl bromide(4.54 mL, 38.6 mmol) was added and the reaction mixture was allowed towarm to RT. After 2 h, the reaction was quenched with saturated aqueousammonium chloride solution (500 mL). The resulting mixture was extractedwith ethyl acetate (500 mL). The organic phase was then washed withbrine (400 mL), was dried over anhydrous sodium sulfate, and wasconcentrated under reduced pressure to afford a colorless oil. The cruderesidue was purified via SiO₂ column chromatography (220 g SiO₂Combiflash HP Gold Column, 0-100% ethyl acetate/hexanes) to affordintermediate 9a (9.49 g, 73%) as a colorless oil.

¹H NMR (400 MHz, DMSO-d₆) δ 7.38-7.19 (m, 10H), 5.68 (app t, J=3.6 Hz,1H), 4.73 (q, J=4.4 Hz, 1H), 4.63 (d, J=12.1 Hz, 1H), 4.49-4.36 (m, 3H),4.24 (br s, 1H), 4.20-4.13 (m, 1H), 3.81 (d, J=11.9 Hz, 1H), 3.56 (d,J=11.9 Hz, 1H), 3.46 (q, J=10.3 Hz, 2H), 1.47 (s, 3H), 1.25 (s, 3H).

LC/MS: t_(R)=1.88 min, MS m/z=423.31 [M+Na]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% acetic acid, Waterwith 0.1% acetic acid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05min 100% ACN, 3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2μl/min.

HPLC: t_(R)=3.79 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

TLC: eluent: 40% ethyl acetate in hexanes, R_(f)=0.4 (UV)

Intermediate9c—(3aR,5R,6S,6aR)-6-(benzyloxy)-5-((benzyloxy)methyl)-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole-5-carbaldehyde

Dess-Martin Periodinane (3.1 g, 7.3 mmol) was added to a solution ofintermediate 9b (1.95 g, 4.87 mmol) in dichloromethane (24.5 mL) at RT.After 1.5 h, the reaction mixture was purified via SiO₂ columnchromatography (80 g SiO₂ Combiflash HP Gold Column, 0-100% ethylacetate/hexanes) to afford intermediate 9c (1.94 g, 100%) as a colorlessoil.

¹H NMR (400 MHz, CDCl₃) δ 9.91 (s, 1H), 7.36-7.11 (m, 10H), 5.84 (d,J=3.4 Hz, 1H), 4.71 (d, J=12.1 Hz, 1H), 4.59 (d, J=12.2 Hz, 1H),4.59-4.58 (m, 1H), 4.52 (d, J=12.0 Hz, 1H), 4.46 (d, J=12.0 Hz, 1H),4.37 (d, J=4.4 Hz, 1H), 3.68 (d, J=11.0 Hz, 1H), 3.61 (d, J=11.0 Hz,1H), 1.60 (s, 3H), 1.35 (s, 3H).

LC/MS: t_(R)=1.99 min, MS m/z=421.25 [M+Na]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% acetic acid, Waterwith 0.1% acetic acid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05min 100% ACN, 3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2μl/min.

HPLC: t_(R)=4.09 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

TLC: eluent: 40% ethyl acetate in hexanes, R_(f)=0.6 (UV)

Intermediate9d—(3aR,5R,6S,6aR)-6-(benzyloxy)-5-((benzyloxy)methyl)-2,2-dimethyl-5-vinyltetrahydrofuro[2,3-d][1,3]dioxole

2.5M n-butyllithium (6.02 mL) was added to a solution ofmethyltriphenylphosphonium bromide (5.38 g, 15.1 mmol) intetrahydrofuran (20 mL) at −78° C. The reaction was allowed to warm to0° C., and a solution of intermediate 9c (2.00 g, 5.02 mmol) intetrahydrofuran (5 mL) was added slowly via syringe. The reactionmixture was allowed to warm to RT, and was stirred for 4 h. The reactionmixture was then quenched with saturated aqueous ammonium chloridesolution (10 mL) and was partitioned between water (200 mL) and ethylacetate (200 mL). The layers were split and the organic layer was washedwith brine (200 mL), dried over anhydrous sodium sulfate, and wasconcentrated under reduced pressure. The crude residue was purified viaSiO₂ column chromatography (120 g SiO₂ Combiflash HP Gold Column, 0-50%ethyl acetate/hexanes) to afford intermediate 9d (1.01 g, 51%) as acolorless oil.

¹H NMR (400 MHz, CDCl₃) δ 7.42-7.17 (m, 10H), 6.19 (dd, J=17.6, 11.0 Hz,1H), 5.76 (d, J=3.9 Hz, 1H), 5.52 (dd, J=17.5, 1.9 Hz, 1H), 5.25 (dd,J=11.1, 1.8 Hz, 1H), 4.76 (d, J=12.3 Hz, 1H), 4.62-4.55 (m, 2H), 4.52(d, J=12.1 Hz, 1H), 4.41 (d, J=12.1 Hz, 1H), 4.25 (d, J=4.9 Hz, 1H),3.32 (d, J=1.5 Hz, 2H), 1.52 (s, 3H), 1.29 (s, 3H)

LC/MS: t_(R)=2.13 min, MS m/z=419.24 [M+Na]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% acetic acid, Waterwith 0.1% acetic acid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05min 100% ACN, 3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2μl/min.

HPLC: t_(R)=4.37 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

TLC: eluent: 50% ethyl acetate in hexanes, R_(f)=0.55 (UV)

Intermediate9e—(3R,4S,5R)-4-(benzyloxy)-5-((benzyloxy)methyl)-2-methoxy-5-vinyltetrahydrofuran-3-ol

4M HCl in dioxane (320 μL) was added to a solution of intermediate 9d(1.01 g, 2.55 mmol) in methanol (12.5 mL) at RT. After 1.25 h, thereaction mixture was partitioned between ethyl acetate (100 mL) andsaturated aqueous sodium bicarbonate solution (100 mL). The phases weresplit and the organic phase was washed with brine (100 mL), was driedover anhydrous sodium sulfate, and was concentrated under reducedpressure to afford crude intermediate 9e (1.05 g, −2.5:1 mixture of 1′anomers) as a colorless oil.

LC/MS: major anomer t_(R)=2.00 min, MS m/z=393.22 [M+Na], minor anomert_(R)=1.98 min, MS m/z=393.22 [M+Na]; LC system: Thermo Accela 1250UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A,50×4.6 mm; Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1%acetic acid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05 min 100%ACN, 3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2 μl/min.

HPLC: major anomer t_(R)=4.01 min, minor anomer t_(R)=3.955 min; HPLCsystem: Agilent 1100 series.; Column: Gemini 5μ C18 110A, 50×4.6 mm;Solvents: Acetonitrile with 0.1% TFA, Water with 0.1% TFA; Gradient: 0min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at 2 mL/min.

TLC: eluent: 25% ethyl acetate in hexanes, Major anomer R_(f)=0.30 (UV),Minor anomer R_(f)=0.25 (UV)

Intermediate9f—(2R,3S,4R)-3,4-bis(benzyloxy)-2-((benzyloxy)methyl)-5-methoxy-2-vinyltetrahydrofuran

NaH (60% wt, 130 mg, 3.2 mmol) was added as a solid to a solution ofintermediate 9e (1.0 g, 2.7 mmol) in THF (13.5 mL) at RT under an argonatmosphere. After 15 min, benzyl bromide (0.38 mL, 3.2 mmol) was addedand the reaction mixture was stirred for 4 h. The reaction mixture wasquenched with saturated aqueous ammonium chloride solution (5 mL) andwas partitioned between ethyl acetate (100 mL) and brine (100 mL). Thephases were split and the organic layer was dried over anhydrous sodiumsulfate, and was concentrated under reduced pressure to afford crudeintermediate 9f (1.57 g, ˜2:1 mixture of 1′ anomers) as a colorless oil.

LC/MS: major anomer t_(R)=1.88 min, MS m/z=483.36 [M+Na], minor anomert_(R)=1.83 min, MS m/z=483.36 [M+Na]; LC system: Thermo Accela 1250UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A,50×4.6 mm; Solvents: Acetonitrile with 0.1% acetic acid, Water with 0.1%acetic acid; Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.2 min 100%ACN, 2.2 min-2.4 min 100%-2% ACN, 2.4 min-2.5 min 2% ACN at 2 μl/min.

HPLC: major anomer t_(R)=4.83 min, minor anomer t_(R)=4.62 min; HPLCsystem: Agilent 1100 series.; Column: Gemini 5μ C18 110A, 50×4.6 mm;Solvents: Acetonitrile with 0.1% TFA, Water with 0.1% TFA; Gradient: 0min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at 2 mL/min.

Intermediate9g—(3R,4S,5R)-3,4-bis(benzyloxy)-5-((benzyloxy)methyl)-5-vinyltetrahydrofuran-2-ol

A solution of TFA (16 mL) and water (1.6 mL) was added to intermediate9f (1.5 g, 3.2 mmol) at 0° C., and the reaction mixture was allowed towarm to RT. After 9 h, water (1 mL) was added and the reaction mixturewas allowed to stir an additional 10 h. The reaction mixture was thenconcentrated under reduced pressure. The crude residue was dissolvedinto ethyl acetate (200 mL) and was washed with saturated aqueous sodiumbicarbonate solution (2×150 mL) and brine (150 mL). The organic layerwas dried over anhydrous sodium sulfate and was concentrated underreduced pressure. The residue was purified via′SiO₂ columnchromatography (24 g SiO₂ Combiflash HP Gold Column, 0-100% ethylacetate/hexanes). The fractions containing the desired product werecombined to afford intermediate 9g (580 mg) as a colorless oil that wasa mixture with other impurities. The mixture was used directly in thefollowing step.

LC/MS: t_(R)=3.13 min, MS m/z=463.88 [M+OH]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% acetic acid, Waterwith 0.1% acetic acid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05min 100% ACN, 3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2μl/min.

HPLC: t_(R)=4.34 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

Intermediate9h—(3R,4S,5R)-3,4-bis(benzyloxy)-5-((benzyloxy)methyl)-5-vinyldihydrofuran-2(3H)-one

Tetrapropylammonium perruthenate (45.7 mg, 130 μmol) and4-methylmorpholine N-oxide (457 mg, 3.89 mmol) were added to a solutionof intermediate 9g (580 mg, 1.30 mmol) and 4A MS (100 mg) in DCM (6.45mL) at RT. After 1 h, silica gel (˜500 mg) was added to the reactionmixture and the resulting slurry was filtered through a plug of silicagel (˜1 g). The filtrate was concentrated under reduced pressure. Thecrude residue was purified via SiO₂ column chromatography (12 g SiO₂Combiflash HP Gold Column, 0-100% ethyl acetate/hexanes) to affordintermediate 9h (254 mg, 18% over two steps) as a colorless oil.

¹H NMR (400 MHz, CDCl₃) δ 7.38-7.23 (m, 13H), 7.20-7.13 (m, 2H), 5.91(dd, J=17.5, 11.2 Hz, 1H), 5.49 (dd, J=17.5, 0.9 Hz, 1H), 5.33 (dd,J=11.2, 0.9 Hz, 1H), 4.96 (d, J=12.0 Hz, 1H). 4.74-4.68 (m, 2H),4.55-4.47 (m, 3H), 4.39 (d, J=11.9 Hz, 1H), 4.20 (d, J=6.0 Hz, 1H), 3.55(d, J=10.8 Hz, 1H), 3.46 (d, J=10.8 Hz, 1H)

LC/MS: t_(R)=2.19 min, MS m/z=444.78 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% acetic acid, Waterwith 0.1% acetic acid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05min 100% ACN, 3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2μl/min.

HPLC: t_(R)=4.53 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

TLC: eluent: 25% ethyl acetate in hexanes, R_(f)=0.45 (UV)

Intermediate9i—(3R,4S,5R)-2-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-3,4-bis(benzyloxy)-5-((benzyloxy)methyl)-5-vinyltetrahydrofuran-2-ol

n-Butyllithium (2.5M in hexanes, 1.0 mL, 2.5 mmol) was added rapidly toa suspension of intermediate 1b (0.21 g, 0.81 mmol) and1,2-bis(chlorodimethylsilyl)ethane (0.17 g, 0.81 mmol) in THF (4 mL) at−78° C. under an argon atmosphere. The resulting mixture was thentransferred via cannula to a solution of 9h (0.18 g, 0.41 mmol) in THF(1 mL) at −78° C. under an argon atmosphere. After 20 min, the reactionmixture was allowed to warm to 0° C. and was stirred for 15 min. Thereaction mixture was quenched with saturated aqueous ammonium chloridesolution (1 mL). The resulting mixture was diluted with ethyl acetate(100 mL) and was washed with saturated aqueous sodium bicarbonatesolution (100 mL) and brine (100 mL). The organic layer was dried overanhydrous sodium sulfate, and was concentrated under reduced pressure.The crude residue was purified via SiO₂ column chromatography (12 g SiO₂Combiflash HP Gold Column, 0-100% ethyl acetate/hexanes) to affordintermediate 9i (11.1 mg, 5%, mixture of isomers) as a colorless oil.

LC/MS: t_(R)=1.97 min, MS m/z=579.27 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% acetic acid, Waterwith 0.1% acetic acid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05min 100% ACN, 3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2μl/min.

HPLC: t_(R)=3.37 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

TLC: eluent: ethyl acetate, R_(f)=0.3 (UV)

Intermediate9j—7-((2S,3S,4S,5R)-3,4-bis(benzyloxy)-5-((benzyloxy)methyl)-5-vinyltetrahydrofuran-2-yl)pyrrolo[2,1-f][1,2,4]triazin-4-amine

To a solution of intermediate 9i (11.0 mg, 19.0 μmol) and triethylsilane(0.5 mL) in DCM (1 mL) was added boron trifluoride diethyl etherate (0.1mL) slowly at 0° C. under an argon atmosphere. After 1 h, the reactionmixture was slowly diluted with saturated aqueous sodium bicarbonatesolution (10 mL), and the resulting mixture was extracted with ethylacetate (2×10 mL), was dried over anhydrous sodium sulfate, and wasconcentrated under reduced pressure. The crude residue was purified viaSiO₂ column chromatography (4 g SiO₂ Combiflash HP Gold Column, 0-100%ethyl acetate/hexanes) to afford intermediate 9j (7.7 mg, 72%) as acolorless film.

¹H NMR (400 MHz, CDCl₃) δ 7.87 (s, 1H), 7.37-7.17 (m, 15H), 6.73 (d,J=4.5 Hz, 1H), 6.51 (d, J=4.5 Hz, 1H), 6.23 (dd, J=17.5, 10.9 Hz, 1H),5.70 (d, J=3.9 Hz, 1H), 5.59 (dd, J=17.5, 1.8 Hz, 1H), 5.32 (dd, J=10.9,1.7 Hz, 1H), 4.72-4.56 (m, 4H), 4.49 (d, J=11.9 Hz, 2H), 4.43 (d, J=5.6Hz, 1H), 4.25 (dd, J=5.6, 4.0 Hz, 1H), 3.56 (s, 2H).

LC/MS: t_(R)=2.32 min, MS m/z=563.33 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% acetic acid, Waterwith 0.1% acetic acid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05min 100% ACN, 3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2μl/min.

HPLC: t_(R)=3.51 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

TLC: eluent: ethyl acetate, R_(f)=0.40 (UV)

Example 20(2R,3S,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-(hydroxymethyl)-2-vinyltetrahydrofuran-3,4-diol

Boron tribromide (1 M, 0.06 mL, 60 μmol) was added dropwise to asolution of intermediate 9j (7.7 mg, 13.7 μmol) in dichloromethane (1mL) at −78° C. under an argon atmosphere. After 1 h, the reactionmixture was allowed to warm to 0° C., and was stirred an additional 1.5h. The reaction was cooled to −78° C. and was quenched with a 2:1methanol/pyridine solution (1.5 mL). The resulting mixture was allowedto warm to RT, and was concentrated under reduced pressure. The cruderesidue was purified by preparatory HPLC (Phenominex Synergi 4u Hydro-RR80A 150×30 mm column, 0-100% acetonitrile/water gradient) to affordexample 20 (0.5 mg, 13%) as a white solid.

¹H NMR (400 MHz, CD₃OD) δ 7.78 (s, 1H), 6.88 (d, J=4.5 Hz, 1H), 6.76 (d,J=4.5 Hz, 1H), 6.02 (dd, J=17.4, 11.0 Hz, 1H), 5.47 (dd, J=17.4, 2.0 Hz,1H), 5.23 (dd, J=10.9, 2.1 Hz, 1H), 5.15 (d, J=8.3 Hz, 1H), 4.72 (dd,J=8.2, 5.7 Hz, 1H), 4.34 (d, J=5.7 Hz, 1H), 3.60 (d, J=11.8 Hz, 1H),3.49 (d, J=11.8 Hz, 1H)

LC/MS: t_(R)=0.84 min, MS m/z=293.19 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% acetic acid, Waterwith 0.1% acetic acid; Gradient: 0 min-1.5 min 2-100% ACN, 1.5 min-2.2min 100% ACN, 2.2 min-2.4 min 100%-2% ACN, 2.4 min-2.5 min 2% ACN at 2μl/min

HPLC: t_(R)=2.181 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

Example 21(2R,3R,4R,5S)-5-(4-amino-5-fluoropyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-azido-4-fluoro-2-(hydroxymethyl)tetrahydrofuran-3-ol

Example 19 (237 mg, 0.766 mmol) and selectfluor (407 mg, 1.15 mmol) weresuspended in acetonitrile (5 mL), and AcOH (0.2 mL) was added. Theresulting mixture was stirred at room temperature for 30 min, and wasthen neutralized with sodium bicarbonate solution and filtered to removesolids. Upon concentration in vacuo, the residue was purified bypreparative HPLC (acetonitrile 0 to 30% in water) to give example 21 (27mg, 11%) as an off-white solid.

¹H NMR (400 MHz, CD₃OD) δ 7.73 (s, 1H), 6.63 (s, 1H), 5.80 (dd, J=23.9,1.7 Hz, 1H), 5.16 (ddd, J=55.3, 5.0, 1.7 Hz, 1H), 4.56 (dd, J=23.5, 5.0Hz, 1H), 3.94-3.60 (m, 2H) ¹⁹F NMR (376 MHz, CD₃OD) δ −161.76 (s),−195.42 (d, J=55.4 Hz)

MS m/z=328 [M+H]. MS system: Thermo LCQ Fleet

Intermediate 11b—2-fluoropyrrolo[2,1-f][1,2,4]triazin-4-amine—

Intermediate 11a (2.0 g, 13.4 mmol) was charged to a polyTube vessel.The reaction vessel was then placed in an ice bath and both 70% HF/Pyr(18 mL) and pyridine (9 mL) were added sequentially. Immediately afterthe addition of pyridine, tBuNO₂ (2.07 mL, 17.43 mmol) was then addedslowly over 20 min. The solution goes from tan to black with an exothermand outgassing. The reaction was then stirred for an additional 20 min,and the reaction mixture was then diluted with water, and wasconcentrated under reduced pressure. The crude residue was partitionedbetween ethyl acetate and water. The organics were separated and theaqueous was washed with ethyl acetate three times. The organics werecombined and washed with brine. The crude was dried over Na₂SO₄,filtered, and the solvent was removed under reduced pressure. The cruderesidue was purified by silica gel chromatography (50-100% EtOAc/Hex) toafford intermediate 11b (1.68 g, 82%) as a tan solid.

¹H NMR (400 MHz, DMSO-d₆) δ 8.49-8.09 (m, 2H), 7.58 (t, J=2.0 Hz, 1H),6.95 (d, J=4.5, 1 H), 6.59 (d, J=4.5, 1 H).

¹⁹F NMR (376 MHz, DMSO-d₆) δ −73.42 (s).

LC/MS: t_(R)=1.03 min, MS m/z=153.08 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80min 100% ACN, 1.8 min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN at 1.8mL/min.

Intermediate 11c—7-bromo-2-fluoropyrrolo[2,1-f][1,2,4]triazin-4-amine

A solution of 11b (3.36 g, 22.1 mmol) in DMF (50 mL) was cooled to 0° C.in an ice bath. A solution of 1,3-dibromo-5,5-dimethylhydantoin (3.16 g,11.0 mmol) in DMF (50 mL) was added dropwise by addition funnel over 40min. After 1 h, the reaction was quenched with sat. Na₂S₂O_(3(aq)) andthe crude was partitioned between EtOAc and 5% LiCl_((aq)). The organicswere extracted with 5% LiCl_((aq)) (4×) followed by brine. The organicswere dried over Na₂SO₄, the solids were removed by filtration, and thefiltrate was concentrated under reduced pressure. The crude residue wassonicated with CH₂Cl₂, and the solids were collected by filtration, andwere dried under high vacuum to afford intermediate 11c (3.93 g, 77%) asa yellow solid.

¹H NMR (400 MHz, DMSO-d₆) δ 8.49-8.44 (m, 2H), 7.08 (d, J=4.6 Hz, 1H),6.76 (d, J=4.6 Hz, 1H).

¹⁹F NMR (376 MHz, DMSO-d₆) δ −71.45 (s).

LC/MS: t_(R)=1.22 min, MS m/z=232.98 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80min 100% ACN, 1.8 min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN at 1.8mL/min.

Intermediate11e—(3R,4R,5R)-2-(4-amino-2-fluoropyrrolo[2,1-f][1,2,4]triazin-7-yl)-4-(benzyloxy)-5-((benzyloxy)methyl)-3-fluorotetrahydrofuran-2-ol

To a solution of 11c (2.09 g, 9.08 mmol) in THF (30 mL) was added1,2-bis(chlorodimethylsilyl)ethane (STABASE, 1.96 g, 9.08 mmol) in oneportion, and the resulting mixture was allowed to stir at ambienttemperature for 1 h. The reaction was then cooled to −78° C. using a dryice bath with methanol. nBuLi (2.5M in hexanes, 10.9 mL, 27.2 mmol) wasadded in a manner to maintain an internal temperature of −65° C. Asolution of intermediate 11d (Prepared according to WO2012012776, 2.5 g,7.5 mmol) in THF (25 mL) was then added to the reaction mixture over 1min. After 5 min, the reaction mixture was quenched with acetic acid andwas allowed to come to ambient temperature. The solvents were removedunder reduced pressure and the residue was taken up into ethyl acetate.The organics were washed with water followed by brine. The layers wereseparated and the organics were dried over Na₂SO₄, filtered, andconcentrated under reduced pressure to afford crude 11e as a mixture ofisomers, which was used as is for the next step.

LC/MS: t_(R)=1.32 and 1.40 min, MS m/z=483.15 [M+H]; LC system: ThermoAccela 1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μXB-C18 100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid,Water with 0.1% formic acid; Gradient: 0 min-1.4 min 2-100% ACN, 1.4min-1.80 min 100% ACN, 1.8 min-1.85 min 100%-2% ACN, 1.85 min-2 min 2%ACN at 1.8 mL/min.

Intermediate11f—7-((2S,3S,4R,5R)-4-(benzyloxy)-5-((benzyloxy)methyl)-3-fluorotetrahydrofuran-2-yl)-2-fluoropyrrolo[2,1-f][1,2,4]triazin-4-amine

Intermediate 11e (1.99 g, 3.72 mmol) was dissolved into CH₂Cl₂ (80 mL)and TES (4.75 mL, 29.7 mmol) was added to the mixture. The reactionmixture was cooled to 0° C. and BF₃.Et₂O (1.07 mL, 4.09 mmol) was slowlyadded. After 15 min, the reaction mixture was quenched with sat.NaHCO_(3(aq)) and the layers were separated. The aqueous layer waswashed with CH₂Cl₂. The organic layers were combined and were washedwith sat. NaHCO_(3(aq)). The organics were dried over Na₂SO₄, filtered,and were concentrated under reduced pressure. The crude was purified bysilica gel chromatography (0-60% EtOAc/Hex) to afford intermediate 11f(1.12 g, 64%, 2:1 mixture of 1′ anomers).

LC/MS: t_(R)=1.55 min, MS m/z=467.47 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80min 100% ACN, 1.8 min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN at 1.8mL/min.

Intermediate11g—(2R,3R,4R,5S)-5-(4-amino-2-fluoropyrrolo[2,1f-][1,2,4]triazin-7-yl)-4-fluoro-2-(hydroxymethyl)tetrahydrofuran-3-ol

Intermediate 11f (0.82 g, 1.76 mmol) was dissolved in acetic acid (25mL). The reaction vessel was purged with Argon and 10% Pd/C (468 mg,0.439 mmol) was added. The vessel was evacuated and backfilled withH_(2(g)) (3×). After 1 h, the reaction vessel was purged with nitrogen.The resulting mixture was filtered through a pad of celite and thefilter cake was washed with CH₃OH. The filtrate was concentrated underreduced pressure and then coevaporated with ethyl acetate followed byhexanes to afford intermediate 11g (503 mg, 98%, 2:1 mixture of 1′anomers).

LC/MS: t_(R)=0.81 min, MS m/z=286.97 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80min 100% ACN, 1.8 min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN at 1.8mL/min.

Intermediate11h—(2S,3R,4R,5S)-5-(4-amino-2-fluoropyrrolo[2,1-f][1,2,4]triazin-7-yl)-4-fluoro-2-(iodomethyl)tetrahydrofuran-3-ol

To an argon purged flask was added a solution of 11g (283 mg, 0.989mmol) in DMF (10 mL) followed by a solution of methyltriphenoxyphosphonium iodide (0.536 g, 1.19 mmol) in 4 mL DMF. Thereaction mixture was allowed to stir at 0° C. for 10 min and was thenwarmed to ambient temperature. After 30 min, the reaction was quenchedwith sat. Na₂S₂O_(3(aq)). The crude material was partitioned betweenEtOAc and 5% LiCl_((aq)). The organics were separated and washed withbrine. The organics were dried over Na₂SO₄, filtered, and concentratedunder reduced pressure. The crude residue was taken up in ACN andpurified by HPLC without acid modifier to afford intermediate 11h (201mg, 52%, 2:1 mixture of 1′ anomers) as a white solid.

LC/MS: t_(R)=1.08 min, MS m/z=397.12 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80min 100% ACN, 1.8 min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN at 1.8mL/min.

Intermediate11i—(3R,4R,5S)-5-(4-amino-2-fluoropyrrolo[2,1-f][1,2,4]triazin-7-yl)-4-fluoro-2-methylenetetrahydrofuran-3-ol

To a solution of 11h (356 mg, 0.899 mmol) in THF (8 mL) was added DBU(0.403 mL, 2.70 mmol) and the resulting mixture was heated to 60° C.After 3 h, the reaction mixture was concentrated under reduced pressure.The crude residue was purified by silica gel chromatography (40-100%EtOAc/Hex) to afford intermediate 11i (201 mg, 83%, 2:1 mixture of 1′anomers) as a white solid.

LC/MS: t_(R)=1.04 min, MS m/z=269.14 [M+1]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80min 100% ACN, 1.8 min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN at 1.8mL/min.

Intermediate11j—(2S,3R,4R,5S)-5-(4-amino-2-fluoropyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-azido-4-fluoro-2-(iodomethyl)tetrahydrofuran-3-ol

Benzyltrimethylammonium chloride (292 mg, 1.57 mmol) and sodium azide(102 mg, 1.57 mmol) were dissolved in ACN (4 mL), and the resultingmixture was stirred at ambient temperature for 4 h. The mixture wasfiltered and the filtrate was added to a solution of 11i (0.201 g, 0.749mmol) in THF (4 mL). NMM (0.412 mL, 3.75 mmol) was added followed by thedropwise addition of a solution of iodine (0.342 g, 1.35 mmol) in THF (4mL). After 15 min, N-acetyl cysteine was added portion wise until nooutgassing was observed. Sat. Na₂S₂O_(3(aq)) was added until thesolution was a light yellow. The resulting mixture was partitionedbetween water and ethyl acetate. The layers were separated and theorganic layer was dried over Na₂SO₄, filtered, and concentrated underreduced pressure. The crude residue was purified by silica gelchromatography (20-100% EtOAc/Hex) to afford intermediate 11j (183 mg,56%) as a single isomer.

¹H NMR (400 MHz, DMSO-d₆) δ 8.44 (d, J=28.6 Hz, 2H), 6.98 (d, J=4.6 Hz,1H), 6.79 (d, J=4.6 Hz, 1H), 6.32 (d, J=6.9 Hz, 1H), 5.60 (dd, J=23.8,2.5 Hz, 1H), 5.36 (ddd, J=54.9, 5.0, 2.6 Hz, 1H), 4.60 (ddd, J=21.5,6.9, 5.0 Hz, 1H), 3.63 (ABq, Δδ=0.09 ppm, J=8 Hz, 2H).

¹⁹F NMR (376 MHz, DMSO-d₆) δ −71.74 (s), −194.57 (ddd, J=54.9, 24.0,21.7 Hz)

LC/MS: t_(R)=1.71 min, MS m/z=437.93 [M+1]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-2.4 min 2-100% ACN, 2.4 min-2.80min 100% ACN, 2.8 min-2.85 min 100%-2% ACN, 2.85 min-3.0 min 2% ACN at1.8 mL/min.

Intermediate11k—(2S,3R,4S5S)-5-(4-amino-2-fluoropyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-azido-4-fluoro-2-(iodomethyl)tetrahydrofuran-3-ylisobutyrate

To a solution of 11j (0.183 g, 0.419 mmol) in THF (10 mL) was addedisobutyric anhydride (0.083 mL, 0.502 mmol), TEA (0.118 mL, 0.837 mmol),and DMAP (10 mg, 0.084 mmol). The reaction was allowed to stir atambient temperature for 15 min, and the reaction was quenched withCH₃OH. The reaction mixture was concentrated under reduced pressure andthe crude residue was purified by silica gel chromatography (0-50%EtOAc/Hex) to afford intermediate 11k (0.198 g, 93%) as a white solid.

¹H NMR (400 MHz, DMSO-d₆) δ 8.48 (d, J=30.7 Hz, 2H), 6.99 (d, J=4.6 Hz,1H), 6.84 (d, J=4.6 Hz, 1H), 5.77-5.47 (m, 3H), 3.69 (ABq, 46=0.05 ppm,J=12 Hz, 2H), 2.70 (p, J=7.0 Hz, 1H), 1.24-1.05 (d, J=7.0 Hz, 6H).

¹⁹F NMR (376 MHz, DMSO-d₆) δ −71.58 (s), −194.89 (ddd, J=55.0, 24.3,16.8 Hz).

LC/MS: t_(R)=1,56 min, MS m/z=508.13 [M+1]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-2.4 min 2-100% ACN, 2.4 min-2.80min 100% ACN, 2.8 min-2.85 min 100%-2% ACN, 2.85 min-3.0 min 2% ACN at1.8 mL/min.

Intermediate11l—((2R,3R,4S,5S)-5-(4-amino-2-fluoropyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-azido-4-fluoro-3-(isobutyryloxy)tetrahydrofuran-2-yl)methyl3-chlorobenzoate

Intermediate 11k (0.153 g, 0.302 mmol) was dissolved in CH₂Cl₂ (10 mL)and H₂O (6 mL). Potassium phosphate dibasic (0.138 g, 0.603 mmol),tetrabutylammonium bisulfate (0.210 g, 0.618 mmol), and 3-chlorobenzoicacid (0.097 g, 0.618 mmol) were added sequentially. The resultingmixture was cooled to 0° C. and MCPBA (0.203 g, 0.905 mmol) was added.The reaction mixture was allowed to warm to ambient temperature and wasstirred for 16 h. The reaction mixture was then quenched with satNa₂S₂O_(3(aq)), and was concentrated under reduced pressure. The crudeaqueous residue was diluted with ACN and purified by preparative HPLCwithout acid modifier to afford intermediate 11l (20 mg, 13%) as a whitesolid.

¹H NMR (400 MHz, DMSO-d₆) δ 8.46 (d, J=26.4 Hz, 2H), 7.96-7.81 (m, 2H),7.81-7.66 (m, 1H), 7.62-7.46 (m, 1H), 6.94 (d, J=4.5 Hz, 1H), 6.80 (d,J=4.5 Hz, 1H), 5.73 (s, 3H), 4.60 (ABq, Δδ=0.08 ppm, J=12 Hz, 2H), 2.66(p, J=7.0 Hz, 1H), 1.20-1.01 (m, 6H).

¹⁹F NMR (376 MHz, DMSO-d₆) δ=−71.45 (s), −193.41 (ddd, J=54.4, 25.4,21.2 Hz,).

LC/MS: t_(R)=2.22 min, MS m/z=536.17 [M+1]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-2.4 min 2-100% ACN, 2.4 min-2.80min 100% ACN, 2.8 min-2.85 min 100%-2% ACN, 2.85 min-3.0 min 2% ACN at1.8 mL/min.

Example 22(2R,3R,4R,5S)-5-(4-amino-2-fluoropyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-azido-4-fluoro-2-(hydroxymethyl)tetrahydrofuran-3-ol

To a solution of intermediate 11l (22 mg, 0.041 mmol) in CH₃OH (1 mL)was added conc. NH₄OH (1 mL) at RT. After 30 min, the reaction mixturewas concentrated under reduced pressure. The crude residue was dilutedwith minimal H₂O and was purified by preparative HPLC without modifierto afford example 22 (10 mg, 77%) as a white solid.

¹H NMR (400 MHz, DMSO-d₆) δ 8.40 (d, J=30.9 Hz, 2H), 6.95 (d, J=4.5 Hz,1H), 6.78 (d, J=4.5 Hz, 1H), 5.89 (d, J=7.5 Hz, 1H), 5.61 (dd, J=23.8,2.1 Hz, 1H), 5.44 (t, J=6.1 Hz, 1H), 5.18 (ddd, J=55.3, 5.1, 2.2 Hz,1H), 4.44 (ddd, J=23.7, 7.5, 5.0 Hz, 1H), 3.59 (ddd, J=48.5, 12.0, 6.1Hz, 2H).

¹⁹F NMR (376 MHz, DMSO-d₆) δ −71.18 (s), −193.48 (dt, J=55.3, 23.8 Hz).

LC/MS: t_(R)=1.13 min, MS m/z=327.86 [M+1]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-2.4 min 2-100% ACN, 2.4 min-2.80min 100% ACN, 2.8 min-2.85 min 100%-2% ACN, 2.85 min-3.0 min 2% ACN at1.8mL/min.

Intermediate12a—(2R,3R,4S,5S)-5-(4-amino-5-fluoropyrrolo[2,1-f][1,2,4]triazin-7-yl)-3-((tert-butyldimethylsilyl)oxy)-2-(((tert-butyldimethylsilyl)oxy)methyl)-4-fluorotetrahydrofuran-2-carbonitrile

To a solution of intermediate 3d (57 mg, 0.109 mmol) in ACN (3 mL), wasadded Selectfluor II in one portion (52 mg, 0.164 mmol). After 1.5 h,the reaction was quenched by the addition of saturated NaHCO_(3(aq)).Ethyl acetate (4 mL) was added and the biphasic mixture was stirredvigorously for 5 min. The reaction was further diluted with EtOAc andsaturated NaHCO_(3(aq)). The layers were separated and the organic phasewas extracted with water and then brine. The organic layer was driedover Na₂SO₄. The drying agent was removed by vacuum filtration and thefiltrate was concentrated under reduced pressure. Intermediate 12a (11mg, 18.7%) was isolated from the concentrated crude material by silicagel column chromatography using the following solvent ramp: 0% EtOAc inhexanes ramping to 70% EtOAc in hexanes, quickly ramping to 100% EtOAconce the starting material elutes off the column.

¹H NMR (400 MHz, CD₃OD) δ 7.72 (s, 1H), 7.55 (s, 1H), 5.65 (dd, J=24.8,2.4 Hz, 1H), 5.38 (dq, J=54.4, 2 Hz, 1H), 4.88 (dd, J=19.2, 4.4 Hz, 1H),3.96 (ABq, Δδ_(AB)=0.141 ppm, J=11 Hz, 2H), 0.99 (s, 9H), 0.86 (s, 9H),0.21 (s, 6H), 0.07 (s, 3H), −0.02 (s, 3H).

¹⁹F NMR (376 MHz, CD₃OD) δ −161.795 (s), −194.806 (ddd, J=54.5, 19.2,18.8 Hz).

LC/MS: R_(T)=2.06 min, MS m/z=540.64 [M+1]; LC system: Thermo Accela1250 UHPLC; MS: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00mm; Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid; Gradient: 0 min-2.4 min 2-100% ACN, 2.4 min-2.8 min 100% ACN, 2.8min-2.85 min 100%-2% ACN, 2.85 min-3 min 2% ACN.

Example 23(2R,3R,4R,5S)-5-(4-amino-5-fluoropyrrolo[2,1-f][1,2,4]triazin-7-yl)-4-fluoro-3-hydroxy-2-(hydroxymethyl)tetrahydrofuran-2-carbonitrile

To a solution of intermediate 12a (29 mg, 0.054 mmol) in THF (2 mL) in apolypropylene tube was added 70% HF.Pyridine in pyridine (51 μL, 1.97mmol) at 0° C., under an N₂ atmosphere. After 1.5 h, the reaction wasremoved from the ice bath. Additional 70% HF.Pyridine in pyridine wasadded after 3 h (150 μL), 5 h 45 min (200 μL), and 21 h 15 min (0.7 mL).The reaction mixture was then stirred for another 24 h at which pointthe reaction mixture was cooled in an ice bath and then quenched withwater and saturated NaHCO_(3(aq)). The mixture was concentrated underreduced pressure and the residue was taken up in DMF. The resultingsolution/suspension was filtered through a syringe filter (Whatman 0.45μm PTFE w/GMF). The filtrate was injected on an HPLC and thesemi-purified product was further purified by silica gel columnchromatography using the following solvent ramp: 0% MeOH in DCM rampingto 20% MeOH in DCM. Product containing fractions were concentrated andthe residue was lyophilized to afford example 23 (5 mg, 30%) as a whitepowder.

¹H NMR (400 MHz, DMF-d₇) δ 7.74 (s, 1H), 6.61 (s, 1H), 5.75 (dd, J=25.2,1.6 Hz, 1H), 5.23 (ddd, J=54.8, 4.8, 1.6 Hz, 1H), 4.64 (dd, J=22, 4.4Hz, 1H), 3.90 (ABq, Δδ_(AB)=0.151 ppm, J=12 Hz, 2H).

¹⁹F NMR (376 MHz, DMF-d₇) δ −161.727 (s), −193.726 (ddd, J=54.5, 22.9,21.8 Hz).

LC/MS: R_(T)=0.81 min, MS m/z=312.13 [M+1]; LC: Thermo Accela 1250UHPLC; MS: Thermo LCQ Fleet; Column: Kinetex 2.6μ C18 100A, 50×3.00 mm;Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid; Gradient: 0 min-2.4 min 2-100% ACN, 2.4 min-2.8 min 100% ACN, 2.8min-2.85 min 100%-2% ACN, 2.85 min-3 min 2% ACN.

Intermediate13a—N-(7-((2S,3S,4R,5R)-4-((tert-butyldimethylsilyl)oxy)-5-(((tert-butyldimethylsilyl)oxy)methyl)-3-fluoro-5-(iodomethyl)tetrahydrofuran-2-yl)pyrrolo[2,1-f][1,2,4]triazin-4-yl)benzamide

To a solution of triphenylphosphine (973 mg, 3.71 mmol) and imidazole(252 mg, 3.71 mmol) in THF (5 mL) was added iodine (253 mg, 1.86 mmol)at room temperature. Upon complete dissolution of iodine, a solution ofcompound 2g (650 mg, 0.93 mmol) in THF (5 mL) was added dropwise slowly.The resulting mixture was stirred at 80° C. for 3 days and was thenconcentrated in vacuo. The residue was purified by silica gel columnchromatography (0 to 50% EtOAc in hexanes) to give intermediate 13a (230mg, 33%) as an oil.

MS m/z=742 [M+H]. MS system: Thermo LCQ Fleet.

Intermediate13b—N-(7-((2S,3S,4R,5R)-4-((tert-butyldimethylsilyl)oxy)-5-(((tert-butyldimethylsilyl)oxy)methyl)-3-fluoro-5-methyltetrahydrofuran-2-yl)pyrrolo[2,1-f][1,2,4]triazin-4-yl)benzamide

Intermediate 13a (200 mg, 0.243 mmol) was dissolved in methanol (10 mL)and under nitrogen atmosphere, 10% Pd/C (100 mg, 0.094 mmol) and TEA(0.035 mL, 0.243 mmol) were added. The resulting mixture was thenstirred under H₂ atmosphere (balloon) at room temperature for 40 min.The resulting mixture was filtered, and concentrated in vacuo and theresidue was purified by silica gel column chromatography (0 to 40% EtOAcin hexanes) to give intermediate 13b (145 mg, 72%) as a white solid with75% purity.

MS m/z=616 [M+H]. MS system: Thermo LCQ Fleet

Example 24(2R,3R,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-4-fluoro-2-(hydroxymethyl)-2-methyltetrahydrofuran-3-ol

Intermediate 13b (145 mg, 75% purity, 0.177 mmol) was dissolved in THF(10 mL) and TBAF (1M in THF, 0.53 mL, 0.531 mmol) was added. Theresulting mixture was stirred at room temperature for 2 h and thenmethanolic ammonia (7N, 10 mL) was added. The resulting mixture wasstirred for 24 h and was concentrated under reduced pressure. The cruderesidue was purified by preparative HPLC (0 to 35% acetonitrile in waterin 20 min) to afford example 24 (30 mg, 60%) as a white solid.

¹H NMR (400 MHz, CD₃OD) δ 7.78 (s, 1H), 6.84 (d, J=4.5 Hz, 1H), 6.76 (d,J=4.5 Hz, 1H), 5.53 (dd, J=21.5, 4.0 Hz, 1H), 5.25 (ddd, J=55.5, 5.3,4.1 Hz, 1H), 4.44 (dd, J=17.2, 5.2 Hz, 1H), 3.65-3.43 (m, 2H), 1.27 (s,3H)

¹⁹F NMR (376 MHz, CD₃OD) δ −197.08 (ddd, J=55.4, 21.5, 17.1 Hz)

MS m/z=282 [M+H]. MS system: Thermo LCQ Fleet.

Intermediate14a—(2S,3R,4S,5R)-2-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-5-(hydroxymethyl)tetrahydrofuran-3,4-diol

Intermediate 1e (2.64 g, 4.91 mmol) was dissolved in acetic acid (50mL). The flask was purged with Argon and 10% Pd/C (1.05 g, 0.982 mmol)was added. The flask was evacuated and backfilled with H_(2(g)) threetimes. The reaction mixture was stirred under an atmosphere of H_(2(g)).After 1 h, the flask was purged with nitrogen and the reaction mixturewas filtered through a celite pad with CH₃OH washings. The filtrate wasconcentrated under reduced pressure and then coevaporated with EtOAcfollowed by hexanes. The residue was placed under high vacuum to affordintermediate 14a (1.31 g, 99%) as a white solid.

¹H NMR (400 MHz, DMSO-d₆) δ 7.80 (s, 1H), 7.66 (s, 2H), 6.82 (d, J=4.4Hz, 1H), 6.66 (d, J=4.4 Hz, 1H), 5.09 (d, J=6.5 Hz, 1H), 5.06-4.56 (m,3H), 4.21 (t, J=5.9 Hz, 1H), 3.93 (t, J=4.9 Hz, 1H), 3.77 (q, J=4.5 Hz,1H), 3.48 (ddd, J=38.9, 11.8, 4.4 Hz, 2H).

LC/MS: t_(R)=0.47 min, MS m/z=267.13 [M+H]; LC system: Thermo Accela1250 UHPLC

MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18 100A, 50×3.00mm; Solvents: Acetonitrile with 0.1% formic acid, Water with 0.1% formicacid; Gradient: 0 min-2.4 min 2-100% ACN, 2.4 min-2.80 min 100% ACN, 2.8min-2.85 min 100%-2% ACN, 2.85 min-3.0 min 2% ACN at 1.8 mL/min.

Intermediate14b—((3aR,4R,6S,6aS)-6-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl)methanol

Intermediate 14a (3.13 g, 11.7 mmol) was dissolved in acetone (80 mL)and TsOH (6.00 g, 31.5 mmol) was added. Triethylorthoformate (6.0 mL,36.1 mmol) was slowly added over 10 min. The resulting mixture wasallowed to stir at ambient temperature overnight. Saturated aqueoussodium carbonate solution was added until the reaction mixture was pH=8.The solids were removed by filtration and the filtrate was concentratedunder reduced pressure. The crude residue was partitioned between EtOAcand brine. The phases were split and the organics were dried overNa₂SO₄, were filtered, and were concentrated under reduced pressure. Thecrude was purified by silica gel chromatography (60-100% EtOAc/Hex-20%MeOH/EtOAc) to afford intermediate 14b (2.55 g, 71%) as a white solid.

¹H NMR (400 MHz, DMSO-d₆) δ 7.83 (s, 1H), 7.71 (s, 2H), 6.83 (d, J=4.4Hz, 1H), 6.73 (d, J=4.5 Hz, 1H), 5.21 (d, J=4.9 Hz, 1H), 5.01 (dd,J=6.6, 4.9 Hz, 1H), 4.84 (t, J=5.7 Hz, 1H), 4.71 (dd, J=6.7, 3.7 Hz,1H), 3.99-3.85 (m, 1H), 3.46 (t, J=5.5 Hz, 2H), 1.48 (s, 3H), 1.29 (s,3H).

LC/MS: t_(R)=0.87 min, MS m/z=307.21 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80min 100% ACN, 1.8 min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN at 1.8mL/min.

Intermediate14c—7-((3aS,4S,6R,6aR)-6-(((tert-butyldimethylsilyl)oxy)methyl)-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl)pyrrolo[2,1-f][1,2,4]triazin-4-amine

Intermediate 14b (2.55 g, 8.32 mmol) was dissolved in DCM (50 mL) andthe mixture was cooled to 0° C. Imidazole (1.70 g, 24.9 mmol) was addedfollowed by TBSCl (1.88 g, 12.5 mmol). After 16 h, the reaction wasquenched with methanol. The resulting mixture was concentrated underreduced pressure and the crude residue was partitioned between water andEtOAc. The organics were dried over Na₂SO₄, were filtered, and wereconcentrated under reduced pressure. The crude residue was purified bysilica gel chromatography (50-100% EtOAc/Hex) to afford intermediate 14c(2.60 g, 74%) as a white solid.

¹H NMR (400 MHz, DMSO-d₆) δ 7.83 (s, 1H), 7.74 (s, 2H), 6.82 (d, J=4.4Hz, 1H), 6.68 (d, J=4.4 Hz, 1H), 5.26 (d, J=4.4 Hz, 1H), 5.00 (dd,J=6.5, 4.5 Hz, 1H), 4.71 (dd, J=6.5, 3.7 Hz, 1H), 3.97 (td, J=5.1, 3.6Hz, 1H), 3.64 (d, J=5.2 Hz, 2H), 1.48 (s, 3H), 1.28 (s, 3H), 0.83 (s,9H), −0.02 (s, 6H).

LC/MS: t_(R)=1.91 min, MS m/z=421.60 [M+1]; LC system: Thermo Accela1250 UHPLC MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-2.4 min 2-100% ACN, 2.4 min-2.80min 100% ACN, 2.8 min-2.85 min 100%-2% ACN, 2.85 min-3.0 min 2% ACN at1.8 mL/min.

Intermediate 14d—tert-butyl(7-((3aS,4S,6R,6aR)-6-(((tert-butyldimethylsilyl)oxy)methyl)-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl)pyrrolo[2,1-f][1,2,4]triazin-4-yl)carbamate

Intermediate 14c (2.59 g, 6.16 mmol) was dissolved in THF (60 mL) andthe resulting solution was cooled to 0° C. Boc₂O (2.69 g, 12.3 mmol) andDMAP (0.3 g, 2.46 mmol) were then added. TEA (2.56 mL, 18.3 mmol) wasslowly added and the reaction mixture was allowed to warm to RT. After 3h, the reaction mixture was cooled to 0° C. and MeOH (10 mL) was addedfollowed conc. NH₄OH_((aq))(50 mL). The resulting mixture was allowed towarm to RT and was stirred overnight. The reaction mixture wasconcentrated under reduced pressure and the crude residue waspartitioned between EtOAc and water. The layers were separated and theorganic layer was dried over Na₂SO₄, was filtered, and was concentratedunder reduced pressure. The crude residue was purified by silica gelchromatography (0-100% EtOAc/Hex) to afford intermediate 14d (2.82 g,88%) as a white solid.

¹H NMR (400 MHz, DMSO-d₆) δ 10.46 (s, 1H), 8.20 (s, 1H), 7.19 (d, J=4.6Hz, 1H), 6.90 (d, J=4.6 Hz, 1H), 5.33 (d, J=4.2 Hz, 1H), 5.02 (dd,J=6.5, 4.3 Hz, 1H), 4.72 (dd, J=6.5, 3.6 Hz, 1H), 4.01 (q, J=5.0 Hz,1H), 3.64 (d, J=5.1 Hz, 2H), 1.49 (s, 9H), 1.32 (d, J=22.7 Hz, 6H), 0.82(s, 9H), −0.03 (s, 6H).

LC/MS: t_(R)=1.89 min, MS m/z=521.27 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-2.4 min 2-100% ACN, 2.4 min-2.80min 100% ACN, 2.8 min-2.85 min 100%-2% ACN, 2.85 min-3.0 min 2% ACN at1.8 mL/min.

Intermediate 14e—tert-butyl(7-((3aS,4S,6R,6aR)-6-(hydroxymethyl)-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl)pyrrolo[2,1-f][1,2,4]triazin-4-yl)carbamate

Intermediate 14d (2.8 g, 5.4 mmol) was dissolved in THF (50 mL), andTBAF (1.0M in THF, 5.92 mL, 5.92 mmol) was added. After 30 min,additional TBAF (1.0M in THF, 5.92 mL, 5.92 mmol) was added. Afteranother 30 min, the reaction mixture was quenched with water and theresulting mixture was extracted with EtOAc (2×). The combine the organiclayers were washed with brine, were dried over Na₂SO₄, were filtered,and were concentrated under reduced pressure. The crude residue waspurified by silica gel chromatography (10-100% EtOAc/Hex) to affordintermediate 14e (2.19 g, 86%) as a white solid.

¹H NMR (400 MHz, DMSO-d₆) δ 10.46 (s, 1H), 8.22 (s, 1H), 7.20 (s, 1H),6.95 (s, 1H), 5.29 (d, J=4.6 Hz, 1H), 5.03 (dd, J=6.6, 4.7 Hz, 1H), 4.85(t, J=5.7 Hz, 1H), 4.72 (dd, J=6.6, 3.6 Hz, 1H), 4.05-3.90 (m, 1H), 3.46(t, J=5.6 Hz, 2H), 1.50 (s, 12H), 1.29 (s, 3H).

LC/MS: t_(R)=1.52 min, MS m/z=407.05 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-2.4 min 2-100% ACN, 2.4 min-2.80min 100% ACN, 2.8 min-2.85 min 100%-2% ACN, 2.85 min-3.0 min 2% ACN at1.8 mL/min.

Intermediate 14f—tert-butyl(7-((3aS,4S,6aS)-6,6-bis(hydroxymethyl)-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl)pyrrolo[2,1-f][1,2,4]triazin-4-yl)carbamate

Intermediate 14e (1.78 g, 4.38 mmol) was dissolved in DMSO (20 mL) andtoluene (15 mL). Pyridine (0.35 mL, 4.38 mmol) and EDCl (1.26 g, 6.56mmol) were added followed by TFA (0.178 mL, 2.39 mmol). After 90 min,additional pyridine (0.35 mL, 4.38 mmol) and EDCl (1.26 g, 6.56 mmol)were added and the reaction mixture was stirred for an additional 30min. The reaction was quenched with water and the resulting mixture wasextracted with CH₂Cl₂. The aqueous was back extracted with CH₂Cl₂. Theorganic layers were combined and were washed with brine, were dried overNa₂SO₄, were filtered, and were concentrated under reduced pressure. Thecrude was put under high vacuum for 15 min then was used as is for thenext step.

The crude residue was dissolved in dioxane (15 mL) and formaldehyde (37%in water, 5.0 mL, 37.2 mmol) and 2N NaOH (5.34 mL, 10.7 mmol) were addedsequentially. After 10 min, the reaction was quenched with AcOH and theresulting mixture was partitioned between sat. NaHCO_(3(aq)) and CH₂Cl₂.The aqueous layer was back extracted with CH₂Cl₂. The organic layerswere combined and were wash with brine, were dried over Na₂SO₄, werefiltered, and were concentrated under reduced pressure. The crude wasplaced under high vacuum for 15 min then were taken directly into thenext reaction.

The crude residue was dissolved in EtOH (50 mL), and NaBH₄ (0.324 g,8.76 mmol) was added in small portions. After 20 min, the reactionmixture was quenched with AcOH and was concentrated under reducedpressure. The crude residue was partitioned between with EtOAc and sat.NaHCO_(3(aq)). The organic layer was split, was dried over Na₂SO₄, wasfiltered, and was concentrated under reduced pressure. The crude residuewas purified by silica gel chromatography (50-100% EtOAc/Hex) to affordintermediate 14f (1.91 g, 68%) as a white solid.

¹H NMR (400 MHz, DMSO-d₆) δ 10.45 (s, 1H), 8.20 (s, 1H), 7.19 (d, J=4.3Hz, 1H), 6.95 (d, J=4.7 Hz, 1H), 5.35 (d, J=5.2 Hz, 1H), 5.06 (t, J=5.7Hz, 1H), 4.79-4.74 (m, 2H), 4.45 (t, J=5.8 Hz, 1H), 3.73-3.46 (m, 3H),3.40-3.30 (m, 1H), 1.50 (s, 12H), 1.27 (s, 3H).

LC/MS: t_(R)=1.45 min, MS m/z=437.09 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-2.4 min 2-100% ACN, 2.4 min-2.80min 100% ACN, 2.8 min-2.85 min 100%-2% ACN, 2.85 min-3.0 min 2% ACN at1.8 mL/min.

Intermediate 14g—tert-butyl(7-((3aS,4S,6S,6aS)-6-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-6-(hydroxymethyl)-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl)pyrrolo[2,1-f][1,2,4]triazin-4-yl)carbamate

Intermediate 14f (1.15 g, 2.63 mmol) was dissolved in CH₂Cl₂ (50 mL) andTEA (0.73 mL, 5.27 mmol) was added. The resulting solution was cooled to0° C. and DMTrCl (1.35 g, 3.95 mmol) was added. After 10 min, thereaction mixture was quenched with CH₃OH as was then diluted withCH₂Cl₂. The resulting mixture was washed with sat NaHCO_(3(aq)) andbrine. The organic layer was dried over Na₂SO₄, was filtered, and wasconcentrated under reduced pressure. The crude residue was purified bysilica gel chromatography (0-100% EtOAc/Hex) to afford 14g (1.95 g, 79%)as an off-white solid.

¹H NMR (400 MHz, DMSO-d₆) δ10.46 (s, 1H), 8.23 (s, 1H), 7.56-7.07 (m,10H), 7.07-6.70 (m, 5H), 5.24 (d, J=5.2 Hz, 1H), 5.04 (t, J=5.9 Hz, 1H),4.93-4.71 (m, 2H), 3.80-3.59 (m, 7H), 3.52 (dd, J=10.9, 4.8 Hz, 1H),3.25 (d, J=9.9 Hz, 1H), 3.09 (d, J=9.9 Hz, 1H), 1.50 (s, 9H), 1.25 (s,3H), 1.21 (s, 3H).

LC/MS: t_(R)=2.54 min, MS m/z=739.28 [M+H]; LC system: Thermo Accela1250 UHPLC MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-2.4 min 2-100% ACN, 2.4 min-2.80min 100% ACN, 2.8 min-2.85 min 100%-2% ACN, 2.85 min-3.0 min 2% ACN at1.8 mL/min.

Intermediate 14h—tert-butyl(7-((3aS,4S,6R,6aS)-6-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-6-(((tert-butyldimethylsilyl)oxy)methyl)-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl)pyrrolo[2,1-f][1,2,4]triazin-4-yl)carbamate

Intermediate 14g (1.53 g, 2.08 mmol) was dissolved in DMF (10 mL) andimidazole (0.42 g, 6.23 mmol) was added followed by TBSCl (0.47 g, 3.11mmol). After 1 h, the reaction was quenched with methanol andpartitioned between EtOAc and 5% LiCl_((aq)). The phases were split andthe organic layer was washed with brine, was dried over Na₂SO₄, wasfiltered, and was concentrated under reduced pressure. The crude residuewas purified by silica gel chromatography (0-50% EtOAc/Hex) to afford14h (1.77 g, 78%) as an off-white solid.

¹H NMR (400 MHz, DMSO-d₆) δ 10.47 (s, 1H), 8.23 (s, 1H), 7.56-6.66 (m,15H), 5.31 (d, J=4.9 Hz, 1H), 5.14 (dd, J=6.5, 4.9 Hz, 1H), 4.73 (d,J=6.5 Hz, 1H), 3.87 (d, J=9.7 Hz, 1H), 3.72 (s, 6H), 3.53 (d, J=9.7 Hz,1H), 3.31 (m, 1H), 3.08 (d, J=9.8 Hz, 1H), 1.50 (s, 9H), 1.25 (s, 3H),1.22 (s, 3H), 0.75 (s, 9H), −0.04 (s, 3H), −0.08 (s, 3H).

LC/MS: t_(R)=2.34 min, MS m/z=853.50 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-1.0 min 2-100% ACN, 1.0 min-2.80min 100% ACN, 2.8 min-2.85 min 100%-2% ACN, 2.85 min-3.0 min 2% ACN at1.8 mL/min.

Intermediate 14i—tert-butyl(7-((3aS,4S,6R,6aS)-6-(((tert-butyldimethylsilyl)oxy)methyl)-6-(hydroxymethyl)-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl)pyrrolo[2,1-f][1,2,4]triazin-4-yl)carbamate

Intermediate 14h (1.38 g, 1.62 mmol) was dissolved in chloroform (20 mL)and the resulting solution was cooled to 0° C. A solution of TsOH (0.34g, 1.78 mmol) in CH₃OH (16 mL) was then add slowly. After 30 min, thereaction was quenched with sat. NaHCO_(3(aq)), and the resulting mixturewas partitioned between EtOAc and brine. The layers were split and theorganic layer was dried over Na₂SO₄, was filtered, and was concentratedunder reduced pressure. The crude residue was purified by silica gelchromatography (0-100% EtOAc/Hex) to afford intermediate 14i (0.84 g,94%) as a white solid.

¹H NMR (400 MHz, DMSO-d₆) δ 10.42 (s, 1H), 8.20 (s, 1H), 7.19 (s, 1H),6.89 (s, 1H), 5.37 (d, J=4.8 Hz, 1H), 5.05 (dd, J=6.2, 4.8 Hz, 1H), 4.71(d, J=6.2 Hz, 1H), 4.51 (t, J=5.5 Hz, 1H), 3.70 (d, J=10.2 Hz, 1H), 3.59(d, J=5.5 Hz, 2H), 3.49 (d, J=10.2 Hz, 1H), 1.49 (s, 12H), 1.28 (s, 3H),0.82 (s, 9H), −0.01 (s, 3H), −0.02 (s, 3H).

LC/MS: t_(R)=1.88 min, MS m/z=551.25 [M+H]; LC system: Thermo Accela1250 UHPLC MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-1.0 min 2-100% ACN, 1.0 min-2.80min 100% ACN, 2.8 min-2.85 min 100%-2% ACN, 2.85 min-3.0 min 2% ACN at1.8mL/min.

Intermediate 14j—tert-butyl(7-((3aS,4S,6R,6aS)-6-(((tert-butyldimethylsilyl)oxy)methyl)-6-cyano-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl)pyrrolo[2,1-f][1,2,4]triazin-4-yl)carbamate

Intermediate 14i (0.838 g, 1.52 mmol) was dissolved in DMSO (5 mL) andtoluene (3 mL). Pyridine (0.14 mL, 1.67 mmol) and EDCl (0.438 g, 2.28mmol) were added followed by TFA (0.057 mL, 0.761 mmol). After 30 min,additional pyridine (0.14 mL, 1.67 mmol) and EDCl (0.438 g, 2.28 mmol)were added. After 1 h, additional pyridine (0.14 mL, 1.67 mmol) and EDCl(0.438 g, 2.28 mmol) were added. After 2 h, the reaction mixture wasquenched with ½ sat. NaHCO_(3(aq)) and was partitioned between EtOAc and½ sat. NaHCO_(3(aq)). The layers were separated and the organic layerwas dried over Na₂SO₄, was filtered, and was concentrated under reducedpressure. The residue was dissolved in CH₂Cl₂ was concentrated underhigh vacuum for 1 h to afford a residue that was used directly in thenext step.

The residue was dissolved in pyridine (8 mL) and hydroxylaminehydrochloride (0.159 g, 2.28 mmol) was added in one portion. After 15min, the reaction mixture was concentrated under reduced pressure andwas partitioned between EtOAc and water. The organic layer was driedover Na₂SO₄, was filtered, and was concentrated under reduced pressure.The crude residue was placed under high vacuum for 30 min and used as isfor the third step.

The crude residue was dissolved in ACN (8 mL). CDI (0.37 g, 2.28 mmol)was added in one portion. After 45 min, additional CDI (0.37 g, 2.28mmol) was added. After 1 h, the reaction was quenched with ½ sat.NaHCO_(3(aq)). The crude was partitioned between EtOAc and ½ sat.NaHCO_(3(aq)). The layers were separated and the organic layer was driedover Na₂SO₄, was filtered, and was concentrated under reduced pressure.The crude residue was purified by silica gel chromatography (0-50%EtOAc/Hex) to afford intermediate 14j (0.72 g, 87%) as a white solid.

¹H NMR (400 MHz, DMSO-d₆) δ 10.53 (s, 1H), 8.25 (s, 1H), 7.21 (s, 1H),7.00 (d, J=4.6 Hz, 1H), 5.62 (d, J=3.6 Hz, 1H), 5.28 (dd, J=6.6, 3.7 Hz,1H), 4.93 (d, J=6.6 Hz, 1H), 3.83 (s, 2H), 1.62 (s, 3H), 1.50 (s, 9H),1.33 (s, 3H), 0.83 (s, 9H), 0.00 (s, 6H).

LC/MS: t_(R)=2.50 min, MS m/z=546.15 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-2.4 min 2-100% ACN, 2.4 min-2.80min 100% ACN, 2.8 min-2.85 min 100%-2% ACN, 2.85 min-3.0 min 2% ACN at1.8 mL/min.

Intermediate14k—(3aS,4R,6S,6aS)-6-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-4-(((tert-butyldimethylsilyl)oxy)methyl)-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxole-4-carbonitrile

Intermediate 14j (0.688 g, 1.26 mmol) was dissolved in CH₂Cl₂ (15 mL).Zinc bromide (0.567 g, 2.52 mmol) was added in one portion and thereaction mixture was stirred at ambient temperature. After 3 h, thereaction mixture was added to a silica load cartridge and was purifiedby silica gel chromatography (40-100% EtOAc/Hex) to afford intermediate14k (0.56 g, 99%) as a white solid.

¹H NMR (400 MHz, DMSO-d₆) δ 7.86 (s, 1H), 7.80 (s, 2H), 6.85 (d, J=4.5Hz, 1H), 6.79 (d, J=4.5 Hz, 1H), 5.55 (d, J=3.7 Hz, 1H), 5.25 (dd,J=6.6, 3.8 Hz, 1H), 4.92 (d, J=6.6 Hz, 1H), 3.82 (s, 2H), 1.61 (s, 3H),1.33 (s, 3H), 0.83 (s, 9H), −0.13 (s, 6H).

LC/MS: t_(R)=2.27 min, MS m/z=446.68 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-2.4 min 2-100% ACN, 2.4 min-2.80min 100% ACN, 2.8 min-2.85 min 100%-2% ACN, 2.85 min-3.0 min 2% ACN at1.8 mL/min.

Intermediate14l—N-(7-((3aS,4S,6R,6aS)-6-(((tert-butyldimethylsilyl)oxy)methyl)-6-cyano-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl)pyrrolo[2,1-f][1,2,4]triazin-4-yl)acetamide

Intermediate 14k (0.20 g, 0.449 mmol) was dissolved in pyridine (2 mL)then acetic anhydride (0.21 mL, 2.24 mmol) was added and the reactionwas stirred at ambient temperature. After 30 min, the reaction mixturewas quenched with methanol and was concentrated under reduced pressure.The crude residue was purified directly by silica gel chromatography(0-100% EtOAc/Hex) to afford intermediate 14l (0.185 g, 85%) as a whitesolid.

¹H NMR (400 MHz, DMSO-d₆) δ 10.87 (s, 1H), 8.31 (s, 1H), 7.24 (d, J=4.7Hz, 1H), 7.05 (d, J=4.7 Hz, 1H), 5.65 (d, J=3.6 Hz, 1H), 5.29 (dd,J=6.6, 3.6 Hz, 1H), 4.93 (d, J=6.6 Hz, 1H), 3.84 (s, 2H), 2.36 (s, 3H),1.62 (s, 3H), 1.33 (s, 3H), 0.83 (s, 9H), 0.00 (s, 3H), −0.01 (s, 3H).

LC/MS: t_(R)=1.14 min, MS m/z=488.38 [M+1]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80min 100% ACN, 1.8 min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN at 1.8mL/min.

Intermediate14m—N-(5-bromo-7-((3aS,4S,6R,6aS)-6-(((tert-butyldimethylsilyl)oxy)methyl)-6-cyano-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl)pyrrolo[2,1-f][1,2,4]triazin-4-yl)acetamide

Intermediate 14l (80 mg, 0.164 mmol) was dissolved in DMF (2 mL) and NBS(29 mg, 0.164 mmol) was added in one portion. After 45 min, the reactionwas diluted with methanol. The solvent was removed under reducedpressure. The crude residue was purified by silica gel chromatography(0-50% EtOAc/Hex) to afford intermediate 14m (50 mg, 54%) as anoff-white solid.

¹H NMR (400 MHz, DMSO-d₆) δ 10.13 (s, 1H), 8.42 (s, 1H), 7.29 (s, 1H),5.65 (d, J=3.2 Hz, 1H), 5.29 (dd, J=6.6, 3.2 Hz, 1H), 4.91 (d, J=6.5 Hz,1H), 3.84 (d, J=1.6 Hz, 2H), 2.27 (s, 3H), 1.62 (s, 3H), 1.33 (s, 3H),0.83 (s, 9H), 0.02 (s, 3H), 0.00 (s, 3H).

LC/MS: t_(R)=1.79 min, MS m/z=566.40 [M+1]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80min 100% ACN, 1.8 min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN at 1.8mL/min.

Intermediate14n—N-(7-((3aS,4S,6R,6aS)-6-(((tert-butyldimethylsilyl)oxy)methyl)-6-cyano-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl)-5-fluoropyrrolo[2,1-f][1,2,4]triazin-4-yl)acetamide

Intermediate 14m (50 mg, 0.088 mmol) was dissolved in THF (2 mL) and thesolution was cooled to −78° C. nBuLi (2.5M in hexanes, 0.071 mL, 0.18mmol) was added. After 5 min, N-fluorobenzenesulfonimide (NSFI, 33.4 mg,0.106 mmol) was added and the reaction mixture was stirred for 5 min.The reaction was then quenched with AcOH. The solvents were removedunder reduced pressure. The crude residue was purified by reverse phaseHPLC to afford intermediate 14n (10 mg, 22%) as a white solid.

¹H NMR (400 MHz, Methanol-d₄) δ 8.13 (s, 1H), 6.80 (s, 1H), 5.65 (d,J=3.5 Hz, 1H), 5.23 (dd, J=6.7, 3.6 Hz, 1H), 4.97 (d, J=6.7 Hz, 1H),3.92 (d, J=1.7 Hz, 2H), 2.37 (s, 3H), 1.70 (s, 3H), 1.38 (s, 3H), 0.90(s, 9H), 0.08 (s, 6H).

¹⁹F NMR (376 MHz, Methanol-d₄) δ −156.43 (s).

LC/MS: t_(R)=1.65 min, MS m/z=506.18 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-2.4 min 2-100% ACN, 2.4 min-2.80min 100% ACN, 2.8 min-2.85 min 100%-2% ACN, 2.85 min-3.0 min 2% ACN at1.8 mL/min.

Example 25(2R,3S,4R,5S)-5-(4-amino-5-fluoropyrrolo[2,1-f][1,2,4]triazin-7-yl)-3,4-dihydroxy-2-(hydroxymethyl)tetrahydrofuran-2-carbonitrile

Intermediate 14n (11 mg, 0.022 mmol) was taken up into a solution of 50%TFA in water at ambient temperature. After 2 h, the reaction mixture wasquenched with solid Na₂CO₃ to achieve a pH=8. The solvent was removedunder reduced pressure and the crude residue was purified by reversephase HPLC. The fractions containing example 25 were combined and setaside and the fractions containing the N6-Acyl were combined andconcentrated under reduced pressure. The N6-Acyl intermediate residuewas taken up in conc. NH₄OH_((aq)) (1 mL) and the mixture was allowed tostir at ambient temperature. After 30 min, the resulting mixture wasconcentrated under reduced pressure and the crude residue was purifiedby HPLC. The fractions containing example 25 were combined with thepreviously set aside fractions containing example 25 to afford example25 (4 mg, 58%) as a white solid.

¹H NMR (400 MHz, Methanol-d₆) δ 7.71 (s, 1H), 6.56 (s, 1H), 5.44 (d,J=5.6 Hz, 1H), 4.48 (t, J=5.6 Hz, 1H), 4.36 (d, J=5.5 Hz, 1H), 3.83((ABq, Δδ=0.05 ppm, J=12 Hz, 2H).

¹⁹F NMR (376 MHz, Methanol-d₄) δ −161.81 (s)

LC/MS: t_(R)=0.47 min, MS m/z=310.13 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×3.00 mm; Solvents: Acetonitrile with 0.1% formic acid, Waterwith 0.1% formic acid; Gradient: 0 min-1.4 min 2-100% ACN, 1.4 min-1.80min 100% ACN, 1.8 min-1.85 min 100%-2% ACN, 1.85 min-2 min 2% ACN at 1.8mL/min.

Intermediate 15a—tert-butyl(7-((3aS,4S,6R,6aS)-6-(((tert-butyldimethylsilyl)oxy)methyl)-6-(chloromethyl)-2,2-dimethyltetrahydrofuro[3,4-d][1,3]dioxol-4-yl)pyrrolo[2,1-f][1,2,4]triazin-4-yl)carbamate

Intermediate 14i (100 mg, 0.18 mmol) was dissolved in anhydrous pyridine(5 mL). Trifluoromethanesulfonyl chloride (23 μL, 0.22 mmol) was addedin one portion and the reaction mixture was stirred for 45 min at RT.Additional trifluoromethanesulfonyl chloride (100 μL) was then added.After 30 min, additional trifluoromethanesulfonyl chloride (100 μL) wasadded. After an additional 30 min, more trifluoromethanesulfonylchloride (100 μL) was added and the reaction was stirred for 30 min, atwhich point the reaction mixture was concentrated under reducedpressure. The crude residue was dissolved in anhydrous DMF (5 mL) andlithium chloride (153 mg, 3.6 mmol) was then added in one portion. Theresulting mixture was stirred at RT for 16 h. The reaction mixture wasdiluted with ethyl acetate (50 mL) and was washed with saturated aqueoussodium chloride solution (3×20 mL). The organic layer was dried overanhydrous sodium sulfate and was concentrated under reduced pressure.The crude residue was purified with silica gel chromatography (0-20%ethyl acetate in hexanes) to afford intermediate 15a.

MS m/z=569.0 [M+H]. MS system: Thermo LCQ Advantage

Example 26(2R,3S,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-(chloromethyl)-2-(hydroxymethyl)tetrahydrofuran-3,4-diol

Intermediate 15a was dissolved in a solution of TFA and water (1:1, 5mL) and the resulting mixture was stirred for 16 h. The reaction mixturewas then concentrated under reduced pressure. The crude residue wasdissolved in aqueous sodium bicarbonate solution and acetonitrile andwas purified with prep HPLC to afford example 26 (19 mg, 34%) as whitepowder.

¹H NMR (400 MHz, D₂O) δ 7.61 (s, 1H), 6.72-6.64 (m, 2H), 5.19 (d, J=9.1Hz, 1H), 4.73-4.66 (m, 1H), 4.28 (d, J=5.2 Hz, 1H), 3.78 (s, 2H),3.72-3.57 (m, 2H). MS m/z=315.3 [M+H]. MS system: Thermo LCQ Advantage

Example 27 (also TP7)((2R,3R,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-azido-4-fluoro-3-hydroxytetrahydrofuran-2-yl)methyltetrahydrogen triphosphate

Example 27 was prepared as the tetra-sodium salt in a manner similar tothat described for example TP4 starting with example 19.

¹H NMR (400 MHz, D₂O) δ 7.76 (s, 1H), 6.83 (d, J=4.4 Hz, 1H), 6.80 (d,J=4.8 Hz, 1H), 5.94 (d, J=25.2 Hz, 1H), 5.24 (dd, J=55.2, 5.2 Hz, 1H),4.78 (dd, J=26.8, 5.2 Hz, 1H), 4.08-4.18 (m, 2H).

¹⁹F NMR (376 MHz, D₂O) δ −193.74-−194.02 (m).

³¹P NMR (162 MHz, D₂O) δ −4.60 (d, J=53.2 Hz, 1P), −10.25 (d, J=48.4 Hz,1P), −20.28 (t, J=48.4 Hz, 1P).

Example 28((2R,3R,4R,5S)-5-(4-amino-5-fluoropyrrolo[2,1f-][1,2,4]triazin-7-yl)-2-azido-4-fluoro-3-hydroxytetrahydrofuran-2-yl)methyltetrahydrogen triphosphate

Example 28 was prepared as the tetra-sodium salt in a manner similar tothat described for example TP4 starting with example 21.

¹H NMR (400 MHz, D₂O) δ 7.64 (s, 1H), 6.60 (s, 1H), 5.90 (d, J=24.4 Hz,1H), 5.20 (dd, J=54.8, 4.8 Hz, 1H), 4.72 (dd, J=27.2, 4.8 Hz, 1H),4.05-4.18 (m, 2H).

¹⁹F NMR (376 MHz, D₂O) δ −161.00 (s), −196.39-−196.69 (m).

³¹P NMR (162 MHz, D₂O) δ −8.24 (d, J=50.4 Hz), −14.20 (d, J=46.0 Hz),−24.08 (t, J=48.4 Hz). MS m/z=567.87 [M+1]. MS system: Thermo LCQAdvantage

Example 29((2R,3R,4R,5S)-5-(4-amino-2-fluoropyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-azido-4-fluoro-3-hydroxytetrahydrofuran-2-yl)methyltetrahydrogen triphosphate

Example 29 was prepared as the tetra-sodium salt in a manner similar tothat described for example TP4 starting with example 22.

¹H NMR (400 MHz, D₂O) δ 6.81 (d, J=4.4 Hz, 1H), 6.75 (d, J=4.8 Hz, 1H),5.81 (d, J=24.4 Hz, 1H), 5.16 (dd, J=54.4, 4.8 Hz, 1H), 4.70 (dd,J=26.8, 4.4 Hz, 1H), 4.02-4.12 (m, 2H).

¹⁹F NMR (376 MHz, D₂O) δ −75.95 (s), −196.51-−196.80 (m).

³¹P NMR (162 MHz, D₂O) δ −8.29 (d, J=53.2 Hz), −14.22 (d, J=48.4 Hz),−24.09 (t, J=48.4 Hz).

MS m/z=567.59 [M+1]. MS system: Thermo LCQ Advantage

Example 30((2R,3R,4R,5S)-5-(4-amino-5-fluoropyrrolo[2,1f-][1,2,4]triazin-7-yl)-2-cyano-4-fluoro-3-hydroxytetrahydrofuran-2-yl)methyltetrahydrogen triphosphate

Example 30 was prepared as the tetra-sodium salt in a manner similar tothat described for example TP4 starting with example 23.

¹H NMR (400 MHz, D₂O) δ 7.64 (s, 1H), 6.57 (s, 1H), 5.87 (d, J=24.8 Hz,1H), 5.26 (dd, J=53.6, 4.0 Hz, 1H), 4.82 (dd, J=25.2, 4, 4 Hz, 1H),4.26-4.35 (m, 2H).

¹⁹F NMR (376 MHz, D₂O) δ −161.05 (s), −194.92-−195.19 (m).

³¹P NMR (162 MHz, D₂O) 5-8.22 (d, J=50.8 Hz), −14.48 (d, J=48.4 Hz),−24.01 (t, J=48.4 Hz).

MS m/z=551.91 [M+1]. MS system: Thermo LCQ Advantage

Example 31 (also TP11)((2R,3R,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-4-fluoro-3-hydroxy-2-methyltetrahydrofuran-2-yl)methyltetrahydrogen triphosphate

Example 31 was prepared as the tetra-sodium salt in a manner similar tothat described for example TP4 starting with example 24

¹H NMR (400 MHz, D₂O) δ 7.66 (s, 1H), 6.78 (d, J=4.8 Hz, 1H), 6.72 (d,J=4.4 Hz, 1H), 5.58 (dd, J=23.6, 2.4 Hz, 1H), 5.16 (ddd, J=55.2, 5.2,2.8 Hz, 1H), 4.51 (dd, J=23.2, 5.2 Hz, 1H), 3.88 (dd, J=11.6, 6.0 Hz,1H), 3.78 (dd, J=10.8, 4.0 Hz, 1H), 1.2 (s, 3H).

¹⁹F NMR (376 MHz, D₂O) δ −195.74-−196.01 (m).

³¹P NMR (162 MHz, D₂O) δ −8.24 (d, J=50.4 Hz), −13.54 (d, J=45.6 Hz),−24.11 (t, J=48.0 Hz).

Example 32 (also TP12)((2R,3S,4R,5S)-5-(4-amino-5-fluoropyrrolo[2,1f-][1,2,4]triazin-7-yl)-2-cyano-3,4-dihydroxytetrahydrofuran-2-yl)methyltetrahydrogen triphosphate

Example 32 was prepared as the tetra-sodium salt in a manner similar tothat described for example TP4 starting with example 25.

¹H NMR (400 MHz, D₂O) δ 7.59 (s, 1H), 0.57 (s, 1H), 5.44 (d, J=6.0 Hz,1H), 4.56 (d, J=5.2 Hz, 1H), 4.48 (dd, J=5.6 Hz, 1H), 4.16 (dd, J=11.6,6.0 Hz, 1H), 4.08 (dd, J=11.2, 5.2 Hz, 1H).

¹⁹F NMR (376 MHz, D₂O) δ −161.25 (s).

³¹P NMR (162 MHz, D₂O) δ −8.29 (d, J=48.4 Hz), −14.49 (d, J=53.2 Hz),−24.15 (t, J=48.4 Hz).

MS m/z=549.90 [M+1]. MS system: Thermo LCQ Advantage

Example 33 (also TP13)((2R,3S,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-(chloromethyl)-3,4-dihydroxytetrahydrofuran-2-yl)methyltetrahydrogen triphosphate

Example 33 was prepared as the tetra-triethylamine salt in a mannersimilar to that described for example TP3 starting with example 26.

¹H NMR (400 MHz, D₂O) δ 7.76 (s, 1H), 6.92 (br s, 1H), 6.85 (br s, 1H),5.32 (d, J=9.6 Hz, 1H), 4.78 (dd, J=8, 6.4 Hz, 1H), 4.53 (d, J=5.6 Hz,1H), 4.08 (dd, J=10.0, 4.0 Hz, 1H), 3.83-3.95 (m, 3H), 3.07 (q, J=7.6Hz, 24H), 1.16 (t, J=7.6 Hz, 36H).

³¹P NMR (162 MHz, D₂O) δ −9.44 (d, J=45.6 Hz), −11.51 (d, J=48.8 Hz),−22.95 (t, J=48.4 Hz).

MS m/z=555.06 [M+1]. MS system: Thermo LCQ Advantage

Example 34 (also PD6) (2S)-2-ethylbutyl2-(((((2R,3R,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-cyano-4-fluoro-3-hydroxytetrahydrofuran-2-yl)methoxy)(phenoxy)phosphoryl)amino)propanoate

Example 1 (3.8 mg, 0.013 mmol) was dissolved in anhydrousN-methyl-2-pyrrolidone (0.2 mL) and THF (0.1 mL) was added under anargon atmosphere. tert-Butyl magnesium chloride (1 M in THF, 20 μL,0.024 mmol) was then added at RT, and white solids precipitated. After 5min, a solution of p-nitrophenylphosphoramidate PD3c (12 mg, 0.026 mmol)in THF (0.1 mL) was added to the reaction mixture in one portion, andthe resulting mixture was heated to 50° C. After 20 h, the reactionmixture was allowed to cool to RT and was then purified directly bypreparatory HPLC (Phenominex Synergi 4u Hydro-RR 80A 150×30 mm column,40-100% acetonitrile/water gradient). The fractions containing thedesired product were combined and were lyophilized to afford example 34(2.9 mg, 37%, 3:2 diastereomeric mixture) as a white solid.

¹H NMR (400 MHz, CD₃OD) δ 7.80 (s, 0.3H), 7.78 (s, 0.6H), 7.38-7.10 (m,5H), 6.85 (br dd, J=4.7, 2.2 Hz, 1H), 6.75-6.71 (m, 1H), 5.54-5.46 (m,1H), 4.65-4.58 (m, 1H), 4.53-4.31 (m, 3H), 4.07-3.84 (m, 3H), 1.54-1.39(m, 1H), 1.38-1.19 (m, 7H), 0.92-0.81 (m, 6H) 29H

³¹P NMR (162 MHz, CD₃OD) δ 3.25 (br s).

LC/MS: t_(R)=1.55 min, MS m/z=603.19 [M+H]; LC system: Thermo Accela1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μ XB-C18100A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% acetic acid, Waterwith 0.1% acetic acid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0 min-3.05min 100% ACN, 3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2% ACN at 2μl/min.

HPLC: t_(R)=2.98 min; HPLC system: Agilent 1100 series.; Column: Gemini5μ C18 110A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with0.1% TFA; Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at2 mL/min.

Example 35 (also PD7) (2S)-ethyl2-(((((2R,3S,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-2-cyano-3,4-dihydroxytetrahydrofuran-2-yl)methoxy)(phenoxy)phosphoryl)amino)propanoate

Example 1 (19 mg, 65.3 μmol) was dissolved in NMP (0.2 mL). THF (0.1 mL)was added followed by tert-butyl magnesium chloride (1.0M solution intetrahydrofuran, 0.098 mL) at RT under an argon atmosphere. After 5 min,a solution of intermediate PD7a (Prepared according to US20120009147A1,51.4 mg, 130 μmol) in THF (0.1 mL) was added, and the resulting mixturewas warmed to 50° C. After 1 h, the reaction mixture was allowed to coolto RT and was purified directly by preparatory HPLC (Phenominex Synergi4u Hydro-RR 80A 150×30 mm column, 5-100% acetonitrile/water gradient).The fractions containing product were combined, and concentrated and theresulting residue was repurified by preparatory HPLC (Phenominex Luna 5uC18 100×30 mm column, 5-100% acetonitrile/water gradient) to affordexample 35 (12 mg, 34%, 3:2 mixture of diastereomers) as a white solid.

¹H NMR (400 MHz, CD₃OD) δ 7.80 (d, J=2.3 Hz, 0.4H), 7.78 (d, J=2.3 Hz,0.6H), 7.36-7.12 (m, 5H), 6.88-6.81 (m, 1H), 6.76-6.70 (m, 1H),5.53-5.46 (m, 1H), 4.66-4.60 (m, 1H), 4.55-4.30 (m, 3H), 4.15-3.98 (m,2H), 3.93-3.79 (m, 1H), 1.30-1.12 (m, 6H).

³¹P NMR (162 MHz, CD₃OD) δ 3.27 (br s).

LC/MS: major diastereomer t_(R)=1.28 min, MS m/z=547.14 [M+H], minordiastereomer t_(R)=1.30 min, MS m/z=547.04 [M+H]; LC system: ThermoAccela 1250 UHPLC; MS system: Thermo LCQ Fleet; Column: Kinetex 2.6μXB-C18 100A, 50×4.6 mm; Solvents: Acetonitrile with 0.1% acetic acid,Water with 0.1% acetic acid; Gradient: 0 min-2.0 min 2-100% ACN, 2.0min-3.05 min 100% ACN, 3.05 min-3.2 min 100%-2% ACN, 3.2 min-3.5 min 2%ACN at 2 μl/min.

HPLC: major diastereomer t_(R)=2.44 min, minor diastereomer t_(R)=2.46min; HPLC system: Agilent 1100 series.; Column: Gemini 5μ C18 110A,50×4.6 mm; Solvents: Acetonitrile with 0.1% TFA, Water with 0.1% TFA;Gradient: 0 min-5.0 min 2-98% ACN, 5.0 min-6.0 min 98% ACN at 2 mL/min.

Also provided are separate embodiments comprising, respectively,compounds of Formula (A), Formula (B), Formula (C), Formula (D), andFormula (E):

wherein, in each instance, X¹ represents an oxygen protecting group andX² represents an amine protecting group.

Useful oxygen protecting groups include a silyl ether protecting groupor a benzyl-type protecting group, including methoxybenzyl groups.

Useful silyl ether protecting groups include Trimethylsilyl (TMS),Triethylsilyl (TES), Dimethylisopropylsilyl (IPDMS),Diethylisopropylsilyl (DEIPS), Dimethylthexylsilyl (TDS),t-Butyldimethylsilyl (TBS or TBDMS), t-Butyldiphenylsilyl (TBDPS),Tribenzylsilyl, Tri-p-xylylxilyl, Triisopropylsilyl (TIPS),Diphenylmethylsilyl (DPMS), Di-t-butylmethylsilyl (DTBMS),Triphenylsilyl (TPS), Methyldiphenyisilyl (MDPS),t-butylmethoxyphenylsilyl, Tris(trimethylsilyl)silyl (sisyl),(2-Hydroxystyryl)dimethylsilyl (HSDMS),(2-Hydroxystyryl)diisopropylsilyl(HSDIS). t-Butylmethoxyphenylsilyl(TBMPS), and t-Butoxydiphenylsilyl (DPTBOS) protecting groups.

Useful benzyl-type protecting groups include benzyl, halogenated benzyl,p-methoxybenzyl, benzyloxymethyl, 2,4-dimethoxybenzyl,3,4-dimethoxybenzyl, 2,6-dimethoxybenzyl, p-CF₃-benzyl, p-methylbenzyl,p-methoxylbenzyl, 3,5-dimethylbenzyl, p-tert-butylbenzyl, o-nitrobenzyl,p-nitrobenzyl, p-halobenzyl, including p-Br-benzyl, 2,6-dichlorobenzyl,p-cyanobenzyl, p-phenylbenzyl, 2,6-difluorobenzyl, p-acylaminobenzyl(PAB), p-azidobenzyl (Azb), 4-azido-3-chlorobenzyl,2-trifluoromethylbenzyl, p-(methylsulfinyl)benzyl, 2-picolyl, 4-picolyl,3-methyl-2-picolyl N-oxido, 2-quinolinylmethyl, diphenylmethyl (DPM),p,p′-dinitrobenzhydryl, triphenylmethyl, alpha-naphthyldiphenylmethyl,p-methoxyphenyldiphenylmethyl, di(p-methoxyphenyl)phenylmethyl,tri(p-methoxyphenyl)methyl, 4,4′,4″-tris(benzoyloxyphenyl)methyl, and2-naphthylmethyl protecting groups.

Useful amine protecting groups include p-methoxybenzyl carbonyl (Moz orMeOZ), acetyl (Ac), benzoyl (Bz), p-methoxybenzyl (PMB),3,4-dimethoxybenzyl (DMPM), p-methoxyphenyl (PMP), tosyl (Ts or Tos),trifluoroacetamide, and trityl protecting groups. Useful amineprotecting groups also include carbamate and amide protecting groups.Examples of carbamate protecting groups include methyl and ethylcarbamates such as 9-fluorenylmethyloxycarbonyl (FMOC),9-(2-sulfo)fluorenylmethyl, 9-(2,7-dibromo)fluorenylmethyl,17-tetrabenzo[a,c,g,i]fluorenylmethyl (Tbfmoc), 2-chloro-3-indenylmethyl(Climoc), benz[f]inden-3-ylmethyl (Bimoc),2,7-di-t-butyl[9-(10,10-dioxo-10,10,10,10-tetrahydrothioxanyl)]methyl(DBD-Tmoc), [2-(1,3-dithianyl)methyl (Dmoc), and1,1-dioxobenzo[b]thiophene-2-ylmethyl (Bsmoc) carbamates.

Examples of useful substituted ethyl carbamates include1,1-dimethyl-2-cyanoethyl, 2-phosphonioethyl (Peoc), 2-methylthioethyl,2-(p-toluenesulfonyl)ethyl, 2,2,2,-trichloroethyl (Troc),2-(trimethylsilyl)ethyl (Teoc), 2-phenylethyl (hZ),1-(1-adamantyl)-1-methylethyl (Adpoc), 1,1-dimethyl-2-bromoethyl,1,1-dimethyl-2-chloroethyl, 1,1-dimethyl-2,2-dibromoethyl (DB-t-BOC),1,1-dimethyl-2,2,2-trichloroethyl (TCBOC),1-methyl-1-(4-biphenylyl)ethyl (Bpoc), di-t-butylphenyl)-1-methylethyl(t-Bumeoc), 2-(2′pyridyl)ethyl, 2-(4′pyridyl)ethyl,2,2-bis(4′-nitrophenyl)ethyl (Bnpeoc),N-(2-pivaloylamino)-1,1,dimethylethyl,2-[(2-nitrophenyl)dithio]-1-phenylethyl (NpSSPeoc),2-(N,N-dicyclohexylcarboxamido)ethyl, t-butyl (Boc or BOC), 1-adamantyl(1-Adoc), 2-adamantyl (2-Adoc), vinyl (Voc), allyl (Aloe or alloc),1-isopropylallyl (lpaoc), cinnamyl (Coc), 4-nitrocinnamyl (Noc),3-(3′-pyridyl)prop-2-enyl (Paloc), 8-quinolyl, and N-hydroxypiperidinyl,carbamates, as well as alkyldithio carbamates, including methyldithio,ethyldithio, isopropyldithio, t-butyldithio, and phenyldithiocarbamates.

Also useful are aryl-containing and substituted aryl-containingcarbamates such as benzyl, p-methoxybenzyl, p-nitrobenzyl,p-bromobenzyl, p-chlorobenzyl, 2,4-dichlorobenzyl,4-methylsulfinylbenzyl (Msz), 9-anthrylmethyl, 4-methylthiophenyl(Mtpc), 1-methyl-1-(triphenylphosphonio)ethyl(2-triphenylphosphonioisopropyl) (Ppoc), 2-dansylethyl (Dnseoc),2-(4-nitrophenyl)ethyl (Npeoc), 4-phenylacetoxybenzyl (PhAcOZ),4-azidobenzyl (ACBZ), 4-azidomethoxybenzyl, m-chloro-p-acyloxybenzyl,p-(dihydroxyboryl)benzyl, carbobenzyloxy (Cbz), 4-benzisoxazolylmethyl(Bic), 2-(trifluoromethyl)-6-chromonylmethyl (Tcroc), phenyl, anddiphenylmethyl carbamates. Additional carbamates include butynyl,cyclopentyl, cyclohexyl, cyclopropylmethyl, 1-methylcyclobutyl,1-methylcyclohexyl, 1,1-dimethylpropynyl, and1-methyl-1-cyclopropylmethyl carbamates.

Useful amide protecting groups for amines include N-formyl, N-acetyl,N-chloroacetyl, N-trichloroacetyl, N-trifluoroacetyl (TFA),N-phenylacetyl, N-3-phenylpropionyl, N-4-pentenoyl, N-picolinoyl,N-3-pyridylcarboxamido, N-benzoylphenylalanyl, N-benzoyl, andN-p-phenylbenzoyl amides.

Antiviral Activity

Another embodiment relates to methods of inhibiting viral infections,comprising the step of treating a sample or subject suspected of needingsuch inhibition with a composition herein.

Considered herein are samples suspected of containing a virus includenatural or man-made materials such as living organisms; tissue or cellcultures; biological samples such as biological material samples (blood,serum, urine, cerebrospinal fluid, tears, sputum, saliva, tissuesamples, and the like); laboratory samples; food, water, or air samples;bioproduct samples such as extracts of cells, particularly recombinantcells synthesizing a desired glycoprotein; and the like. Typically thesample will be suspected of containing an organism which induces a viralinfection, frequently a pathogenic organism such as a tumor virus.Samples can be contained in any medium including water and organicsolvent\water mixtures. Samples include living organisms such as humans,and manmade materials such as cell cultures.

If desired, the anti-virus activity of a compound after application ofthe composition can be observed by any method including direct andindirect methods of detecting such activity. Quantitative, qualitative,and semiquantitative methods of determining such activity are allcontemplated. Typically one of the screening methods described above areapplied, however, any other method such as observation of thephysiological properties of a living organism are also applicable.

The antiviral activity of a compound can be measured using standardscreening protocols that are known. For example, the antiviral activityof a compound can be measured using the following general protocols.

Respiratory Syncytial Virus (RSV) Antiviral Activity and CytotoxicityAssays

Anti-RSV Activity

Antiviral activity against RSV is determined using an infectiouscytopathic cell protection assay in HEp-2 cells. In this assay,compounds inhibiting viral infection and/or replication produce acytoprotective effect against the virus-induced cell killing that can bequantified using a cell viability reagent. The techniques used here arenovel adaptations of methods described in published literature (Chapmanet al., Antimicrob Agents Chemother. 2007, 51(9):3346-53.)

HEp-2 cells are obtained from ATCC (Manassas, VI) and maintained in MEMmedia supplemented with 10% fetal bovine serum andpenicillin/streptomycin. Cells are passaged twice a week and kept atsubconfluent stage. Commercial stock of RSV strain A2 (AdvancedBiotechnologies, Columbia, Md.) is titered before compound testing todetermine the appropriate dilution of the virus stock that generatesdesirable cytopathic effect in HEp-2 cells.

For antiviral tests, HEp-2 cells are grown in large cell culture flasksto near confluency but not fully so. The compounds to be tested areprediluted in DMSO in 384-well compound dilution plates, either in an 8or 40 sample per plate standardized dose response format. 3-fold serialdilution increments of each test compound are prepared in the plates andtest samples are transferred via acoustic transfer apparatus (Echo,Labcyte) at 100 nl per well into cell culture assay 384-well plates.Each compound dilution is transferred in single or quadruplicate samplesinto dry assay plates, which are stored until assay is ready to go. Thepositive and negative controls are laid out in opposite on ends of theplate in vertical blocks (1 column).

Subsequently, an infectious mixture is prepared using an appropriatedilution of virus stock previously determined by titration with cells ata density of 50,000/ml and 20 uL/well is added to test platesw/compounds via automation (uFlow, Biotek). Each plate includes negativeand positive controls (16 replicates each) to create 0% and 100% virusinhibition standards, respectively. Following the infection with RSV,testing plates are incubated for 4 days in a 37° C. cell cultureincubator. After the incubation, a cell viability reagent, Cell TiterGlo(Promega, Madison, Wis.) is added to the assay plates, which areincubated briefly, and a luminescent readout is measured (Envision,Perkin Elmer) in all the assay plates. The RSV-induced cytopathiceffect, percentage inhibition, is determined from the levels ofremaining cell viability. These numbers are calculated for each testedconcentration relative to the 0% and 100% inhibition controls, and theEC₅₀ value for each compound is determined by non-linear regression as aconcentration inhibiting the RSV-induced cytopathic effect by 50%.Various potent anti-RSV tool compounds are used as positive controls forantiviral activity.

Cytotoxicity Assay in HEp-2 Cells

Cytotoxicity of tested compounds is determined in uninfected HEp-2 cellsin parallel with the antiviral activity using the cell viability reagentin a similar fashion as described before for other cell types (Cihlar etal., Antimicrob Agents Chemother. 2008, 52(2):655-65.). The sameprotocol as for the determination of antiviral activity is used for themeasurement of compound cytotoxicity except that the cells are notinfected with RSV. Instead, an uninfected cell mixture at the samedensity is added at 20 ul/well to plates containing predilutedcompounds, also at 100 nl/sample. Assay plates are then incubated for 4days followed by a cell viability test using the same CellTiter Gloreagent addition and measurement of luminescent readouts. Untreated celland cells treated at 2 uM puromycin (Sigma, St. Louis, Mo.) serve as100% and 0% cell viability control, respectively. The percent of cellviability is calculated for each tested compound concentration relativeto the 0% and 100% controls and the CC₅₀ value is determined bynon-linear regression as a compound concentration reducing the cellviability by 50%.

Cytotoxicity Assay in MT-4 Cells

The MT-4 cell line was obtained from the NIH AIDS Research and ReferenceReagent Program (Germantown, Md.) and cultured in RPMI-1640 medium(Irvine Scientific, Santa Ana, Calif., Cat #9160) supplemented with 10%FBS, 100 units/mL penicillin, 100 units/mL streptomycin, and 2 mML-Glutamine. The MT-4 cells were passaged twice per week to maintaincell densities below 0.6×10⁶ cells/mL. Complete RPMI-1640 mediacontaining 100× concentrations of 3-fold serially diluted compound,ranging from 26 nM to 530 μM, were stamped in quadruplicate into black384-well plates. After compound addition, 2×10³ MT-4 cells were added toeach well using a MicroFlo liquid dispenser (BioTek, Winooski, Vt.) andthe cells were cultured for 5 days at 37° C. in a 5% CO₂ incubator.Following the incubation the cells were allowed to equilibrate to 25° C.and cell viability was determined by adding 25 μL of Cell-Titer Gloviability reagent. The mixture was incubated for 10 minutes at 25° C.,and the luminescence signal was quantified on a Victor Luminescenceplate reader. The CC₅₀ value is defined as the concentration of compoundthat reduces cell viability by 50% as determined by the Cell-Titer Glosignal. The data were analyzed using Pipeline Pilot Plate Data AnalyticsCollection software (Version 7.0, Accelrys, San Diego, Calif.). CC₅₀values were calculated from a non-linear regression analysis using a4-parameter sigmoidal dose-response equation:Y=Bottom+(Top−Bottom)/(1+10̂[(Log CC50−X)*HillSlope]) where the Top andBottom were fixed at 100% and 0% cell viability, respectively. CC₅₀values were calculated as the average±standard deviation of 3independent experiments.

Example EC₅₀/μM HEp-2 CC₅₀/μM MT-4 CC₅₀/μM  1 7.3 >50 >53  29.6 >100 >106  3 2.0 >100 >106  4 30 >50 >53  5 2.1 >50 >53 10 (PD1) 1.039 7.3 11 (PD2) 1.2 42 19.7 12 (PD3) 3.0 >50 27 13 10.5 >100 >106 1440 >100 >106 15 (PD4) 1.6 35 7.9 16 (PD5) 0.3 18 25 19 0.40 >44 1620 >50 >50 21 50 36 15 22 0.57 >100 32 23 23.5 72 21 24 1.0 >100 11 259.2 >100 >93 26 >50 42 >57 34 (PD6) 0.21 >50 >50 35 (PD7) 0.34 >50 47Another benefit relates to advantage that compounds bearing R⁴substitution provides in comparison to compounds lacking R⁴ substitution(i.e. those in which R⁴=H) with regard to MT-4 cytotoxicity. Forexample, compound(2S,3R,4S,5R)-2-(4-aminopyrrolo[1,2-t][1,2,4]triazin-7-yl)-5-(hydroxymethyl)tetrahydrofuran-3,4-diol(Patil, S. A.; Otter, R. A.; Klein, R. S. Tetrahedron Lett. 1994, 35,5339-5342), having the structure:

exhibits a MT-4 CC₅₀=0.007 μM; whereas Examples 1, 4, 5, 20, and 26 allexhibit a MT-4 CC₅₀>53 μM. Furthermore, compound(2R,3R,4R,5S)-5-(4-aminopyrrolo[1,2-f][1,2,4]triazin-7-yl)-4-fluoro-2-(hydroxymethyl)tetrahydrofuran-3-ol(WO2012037038A1), having the structure:

exhibits a MT-4 CC₅₀=30 μM; whereas Examples 2, 3, 13, and 14 allexhibit a MT-4 CCs>106 μM.Another benefit relates to advantage that R³=F compounds bearing R⁴substitution provides in comparison to compounds lacking R⁴ substitution(i.e. those in which R⁴=H) with regard to HEp-2 anti-RSV activity. Forexample the compound(2R,3R,4R,5S)-5-(4-aminopyrrolo[1,2-f][1,2,4]triazin-7-yl)-4-fluoro-2-(hydroxymethyl)tetrahydrofuran-3-ol(WO2012037038A1) having the structure above has a HEp-2 EC₅₀=>100 μM;whereas examples 2, 3, 13, 14, 19, 21, 22, 23, and 24 all exhibitEC₅₀=<100 uM.

RSV RNP Preparation

RSV ribonucleoprotein (RNP) complexes were prepared from a methodmodified from Mason at al (1). HEp-2 cells were plated at a density of7.1×10⁴ cells/cm² in MEM+10% fetal bovine serum (FBS) and allowed toattach overnight at 37° C. (5% CO₂). Following attachment, the cellswere infected with RSV A2 (M01=5) in 35 mL MEM+2% FBS. At 20 hourspost-infection, the media was replaced with MEM+2% FBS supplemented with2 μg/mL actinomycin D and returned to 37° C. for one hour. The cellswere then washed once with PBS and treated with 35 mL of PBS+250 μg/mLlyso-lecithin for one minute, after which all liquid was aspirated. Thecells were harvested by scrapping them into 1.2 mL of buffer A [50 mMTRIS acetate (pH 8.0), 100 mM potassium acetate, 1 mM DTT and 2 μg/mLactinomycin D] and lysed by repeated passage through an 18 gauge needle(10 times). The cell lysate was placed in ice for 10 minutes and thencentrifuged at 2400g for 10 minutes at 4° C. The supernatant (S1) wasremoved and the pellet (P1) was disrupted in 600 uL of Buffer B [10 mMTRIS acetate (pH 8.0), 10 mM potassium acetate and 1.5 mM MgCl₂]supplemented with 1% Triton X-100 by repeated passage through an 18gauge needle (10 times). The resuspended pellet was placed in ice for 10minutes and then centrifuged at 2400g for 10 minutes at 4° C. Thesupernatant (S2) was removed and the pellet (P2) was disrupted in 600 uLof Buffer B supplemented with 0.5% deoxycholate and 0.1% Tween 40. Theresuspended pellet was placed in ice for 10 minutes and then centrifugedat 2400g for 10 minutes at 4° C. The supernatant (S3) fraction,containing the enriched RSV RNP complexes, was collected and the proteinconcentration determined by UV absorbance at 280 nm. Aliquoted RSV RNPS3 fractions were stored at −80° C.

RSV RNP Assay

Transcription reactions contained 25 μg of crude RSV RNP complexes in 30μL of reaction buffer [50 mM TRIS-acetate (pH 8.0), 120 mM potassiumacetate, 5% glycerol, 4.5 mM MgCl₂, 3 mM DTT, 2 mMethyleneglycol-bis(2-aminoethylether)-tetraacetic acid (EGTA), 50 μg/mLBSA, 2.5 U RNasin (Promega), ATP, GTP, UTP, CTP and 1.5 uCi [α-³²P] NTP(3000 Ci/mmol)]. The radiolabeled nucleotide used in the transcriptionassay was selected to match the nucleotide analog being evaluated forinhibition of RSV RNP transcription. Cold, competitive NTP was added ata final concentration of one-half its K_(m) (ATP=20 μM, GTP=12.5 μM,UTP=6 μM and CTP=2 μM). The three remaining nucleotides were added at afinal concentration of 100 μM.

To determine whether nucleotide analogs inhibited RSV RNP transcription,compounds were added using a 6 step serial dilution in 5-foldincrements. Following a 90 minute incubation at 30° C., the RNPreactions were stopped with 350 μL of Qiagen RLT lysis buffer and theRNA was purified using a Qiagen RNeasy 96 kit. Purified RNA wasdenatured in RNA sample loading buffer (Sigma) at 65° C. for 10 minutesand run on a 1.2% agarose/MOPS gel containing 2M formaldehyde. Theagarose gel was dried and exposed to a Storm phosphorimager screen anddeveloped using a Storm phosphorimager (GE Healthcare). Theconcentration of compound that reduced total radiolabeled transcripts by50% (IC₅₀) was calculated by non-linear regression analysis of tworeplicates.

REFERENCE

-   Mason, S., Lawetz, C., Gaudette, Y., Do, F., Scouten, E., Lagace,    L., Simoneau, B. and Liuzzi, M. (2004) Polyadenylation-dependent    screening assay for respiratory syncytial virus RNA transcriptase    activity and identification of an inhibitor. Nucleic Acids Research,    32, 4758-4767.

Example IC₅₀/μM  6 (TP1) 0.086  7 (TP2) 1  8 (TP3) 0.025  9 (TP4) 0.1217 (TP5) 0.56 18 (TP6) 0.42 27 (TP7) 0.097 28 (TP8) 0.086 29 (TP9) 0.08030 (TP10) 31 (TP11) 32 (TP12) 0.022 33 (TP13)

A further consideration relates to advantage that compounds exemplifiedexhibit potent inhibition of the RSV RNP transcription in comparison tocompounds with 2′CMe substitution. For example,((2R,3R,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-3,4-dihydroxy-4-methyltetrahydrofuran-2-yl)methyltetrahydrogen triphosphate (WO2008089105A2, and WO2010002877A2), havingthe structure:

exhibits an IC₅₀=8.5 μM; whereas Example TP3 exhibits an IC₅₀=0.025 μM.Furthermore, compound((2R,3R,4R,5S)-5-(4-aminopyrrolo[2,1-f][1,2,4]triazin-7-yl)-4-fluoro-3-hydroxy-4-methyltetrahydrofuran-2-yl)methyltetrahydrogen triphosphate (WO 2011035231 A1), having the structure:

exhibits an IC₅₀=>100 μM; whereas Examples TP1 exhibits an IC₅₀=0.086μM. and TP2 exhibits an IC₅₀=1 μM.

What is claimed:
 1. A compound of Formula (I), or a pharmaceuticallyacceptable salt thereof:

wherein: R¹ is H or F; R² is H or F; R³ is OH or F; R⁴ is ON, C₁-C₄alkyl, C₂-C₄ alkenyl, C₂-C₄ alkynyl, C₃-C₄ cycloalkyl, azido, halogen,or C₁-C₂ haloalkyl, with the proviso that, when R³ is F, R⁴ is notmethyl; R⁶ is OH; R⁵ is selected from the group of H and:

wherein: n′ is selected from 1, 2, 3, and 4; R⁸ is selected from C₁-C₈alkyl, —O—C₁-C₈ alkyl, benzyl, —O-benzyl, —CH₂—C₃-C₆ cycloalkyl,—O—CH₂—C₃-C₆ cycloalkyl, and CF₃; R⁹ is selected from phenyl,1-naphthyl, 2-naphthyl,

R¹⁰ is selected from H and CH₃; R¹¹ is selected from H or C₁-C₆ alkyl;R¹² is selected from H, C₁-C₈ alkyl, benzyl, C₃-C₆ cycloalkyl, and—CH₂—C₃-C₆ cycloalkyl.
 2. A compound according to claim 1, or apharmaceutically acceptable salt thereof, wherein both R¹ and R² are H,and R³ is OH.
 3. A compound according to claim 1, or a pharmaceuticallyacceptable salt thereof, wherein both R¹ and R² are H, R³ is F.
 4. Acompound according to claim 1, or a pharmaceutically acceptable saltthereof, of Formula (II):

wherein: R³ is OH or F; R⁴ is CN, C₁-C₄ alkyl, C₂-C₄ alkenyl, C₂-C₄alkynyl, C₃-C₄ cycloalkyl, azido, halogen, or C₁-C₂ haloalkyl, with theproviso that, when R³ is F, R⁴ is not methyl; R⁵ is selected from thegroup of H and:

wherein: n′ is selected from 1, 2, 3, and 4; R⁸ is selected from C₁-C₈alkyl, —O—C₁-C₈ alkyl, benzyl, —O-benzyl, —CH₂—C₃-C₆ cycloalkyl,—O—CH₂—C₃-C₆ cycloalkyl, and CF₃; R⁹ is phenyl; R¹⁰ is selected from Hand CH₃; R¹¹ is selected from H or C₁-C₆ alkyl; R¹² is selected from H,C₁-C₈ alkyl, benzyl, C₃-C₆ cycloalkyl, and —CH₂—C₃-C₆ cycloalkyl.
 5. Acompound according to claim 4, or a pharmaceutically acceptable saltthereof, wherein R⁴ is CN, methyl, ethyl, ethenyl, ethynyl, azido, F,Cl, —CH₂Cl, —CH₂F, —CHF₂, or —CF₃.
 6. A compound according to claim 5,or a pharmaceutically acceptable salt thereof, wherein R³ is F.
 7. Acompound according to claim 5, or a pharmaceutically acceptable saltthereof, wherein R³ is OH.
 8. A compound according to claim 5, or apharmaceutically acceptable salt thereof, wherein R³ is F and R⁴ is CN.9. A compound according to claim 5, or a pharmaceutically acceptablesalt thereof, wherein R³ is OH and R⁴ is CN.
 10. A compound according toclaim 5, or a pharmaceutically acceptable salt thereof, wherein R³ is F,and R⁴ is methyl, ethyl, vinyl, or ethynyl.
 11. A compound according toclaim 5, or a pharmaceutically acceptable salt thereof, wherein R³ isOH, and R⁴ is methyl, ethyl, vinyl, or ethynyl.
 12. A compound accordingto claim 5, or a pharmaceutically acceptable salt thereof, wherein R³ isF and R⁴ is halomethyl.
 13. A compound according to claim 5, or apharmaceutically acceptable salt thereof, wherein R³ is OH and R⁴ ishalomethyl.
 14. A compound according to claim 5, or a pharmaceuticallyacceptable salt thereof, wherein R⁵ is H.
 15. A compound according toclaim 5, or a pharmaceutically acceptable salt thereof, wherein R⁵ isselected from the group of:

wherein: R⁸ is selected from C₁-C₈ alkyl, —O—C₁-C₈ alkyl, benzyl, and—CH₂—C₃-C₆ cycloalkyl; and R¹² is selected from C₁-C₈ alkyl, benzyl,C₃-C₆ cycloalkyl, and —CH₂—C₃-C₆ cycloalkyl.
 16. A compound according toclaim 15, or a pharmaceutically acceptable salt thereof, wherein R⁸ andR⁹ are each C₁-C₈ alkyl.
 17. A compound according to claim 15, or apharmaceutically acceptable salt thereof, wherein R⁸ and R⁹ are eachselected from C₁-C₆ alkyl.
 18. A compound according to claim 15, or apharmaceutically acceptable salt thereof, wherein R⁸ and R⁹ are eachselected from C₁-C₄ alkyl.
 19. A compound according to claim 15, or apharmaceutically acceptable salt thereof, wherein R⁵ is selected fromthe group of H and:


20. A compound according to claim 1, or a pharmaceutically acceptablesalt thereof, selected from the group of:


21. A compound according to claim 1, or a pharmaceutically acceptablesalt thereof, selected from the group of:


22. A compound according to claim 1, or a pharmaceutically acceptablesalt thereof, selected from the group of:


23. A compound according to claim 1, or a pharmaceutically acceptablesalt thereof, selected from the group of:


24. A compound according to claim 1, or a pharmaceutically acceptablesalt thereof, selected from the group of:


25. A compound according to claim 1, or a pharmaceutically acceptablesalt thereof, selected from the group of:


26. A method of treating Pneumovirinae virus infection in a human, themethod comprising administering to the human a therapeutically effectiveamount of a compound of claim 1, or a pharmaceutically acceptable saltthereof.
 27. The method of claim 26 wherein the Pneumovirinae virusinfection in a human is a human respiratory syncytial virus infection.28. A pharmaceutical formulation comprising a pharmaceutically effectiveamount of a compound of claim 1, or a pharmaceutically acceptable saltthereof, and a pharmaceutically acceptable carrier or excipient.
 29. Acompound selected from Formula (A), Formula (B), Formula (C), Formula(D), and Formula (E):

wherein X¹ is an oxygen protecting group and X² is an amine protectinggroup.
 30. A compound of claim 29 selected from: